diff --git a/cmd-choose-client.c b/cmd-choose-client.c
index dd09fe51..0aa66622 100644
--- a/cmd-choose-client.c
+++ b/cmd-choose-client.c
@@ -43,7 +43,7 @@ const struct cmd_entry cmd_choose_client_entry = {
 };
 
 struct cmd_choose_client_data {
-	u_int		 client;
+	struct client	*client;
 	char   		*template;
 };
 
@@ -87,7 +87,8 @@ cmd_choose_client_exec(struct cmd *self, struct cmd_ctx *ctx)
 		cdata->template = xstrdup(data->arg);
 	else
 		cdata->template = xstrdup("detach-client -t '%%'");
-	cdata->client = server_client_index(ctx->curclient);
+	cdata->client = ctx->curclient;
+	cdata->client->references++;
 
 	window_choose_ready(wl->window->active,
 	    cur, cmd_choose_client_callback, cmd_choose_client_free, cdata);
@@ -99,23 +100,22 @@ void
 cmd_choose_client_callback(void *data, int idx)
 {
 	struct cmd_choose_client_data	*cdata = data;
-	struct client  			*c, *c2;
+	struct client  			*c;
 	struct cmd_list			*cmdlist;
 	struct cmd_ctx			 ctx;
 	char				*template, *cause;
 
 	if (idx == -1)
 		return;
-	if (cdata->client > ARRAY_LENGTH(&clients) - 1)
+	if (cdata->client->flags & CLIENT_DEAD)
 		return;
-	c = ARRAY_ITEM(&clients, cdata->client);
 
 	if ((u_int) idx > ARRAY_LENGTH(&clients) - 1)
 		return;
-	c2 = ARRAY_ITEM(&clients, idx);
-	if (c2 == NULL || c2->session == NULL)
+	c = ARRAY_ITEM(&clients, idx);
+	if (c == NULL || c->session == NULL)
 		return;
-	template = cmd_template_replace(cdata->template, c2->tty.path, 1);
+	template = cmd_template_replace(cdata->template, c->tty.path, 1);
 
 	if (cmd_string_parse(template, &cmdlist, &cause) != 0) {
 		if (cause != NULL) {
@@ -129,7 +129,7 @@ cmd_choose_client_callback(void *data, int idx)
 	xfree(template);
 
 	ctx.msgdata = NULL;
-	ctx.curclient = c;
+	ctx.curclient = cdata->client;
 
 	ctx.error = key_bindings_error;
 	ctx.print = key_bindings_print;
@@ -146,6 +146,7 @@ cmd_choose_client_free(void *data)
 {
 	struct cmd_choose_client_data	*cdata = data;
 
+	cdata->client->references--;
 	xfree(cdata->template);
 	xfree(cdata);
 }
diff --git a/cmd-choose-session.c b/cmd-choose-session.c
index 87b3437b..7bc34853 100644
--- a/cmd-choose-session.c
+++ b/cmd-choose-session.c
@@ -43,7 +43,7 @@ const struct cmd_entry cmd_choose_session_entry = {
 };
 
 struct cmd_choose_session_data {
-	u_int		 client;
+	struct client	*client;
 	char   		*template;
 };
 
@@ -87,7 +87,8 @@ cmd_choose_session_exec(struct cmd *self, struct cmd_ctx *ctx)
 		cdata->template = xstrdup(data->arg);
 	else
 		cdata->template = xstrdup("switch-client -t '%%'");
-	cdata->client = server_client_index(ctx->curclient);
+	cdata->client = ctx->curclient;
+	cdata->client->references++;
 
 	window_choose_ready(wl->window->active,
 	    cur, cmd_choose_session_callback, cmd_choose_session_free, cdata);
@@ -99,7 +100,6 @@ void
 cmd_choose_session_callback(void *data, int idx)
 {
 	struct cmd_choose_session_data	*cdata = data;
-	struct client  			*c;
 	struct session			*s;
 	struct cmd_list			*cmdlist;
 	struct cmd_ctx			 ctx;
@@ -107,9 +107,8 @@ cmd_choose_session_callback(void *data, int idx)
 
 	if (idx == -1)
 		return;
-	if (cdata->client > ARRAY_LENGTH(&clients) - 1)
+	if (cdata->client->flags & CLIENT_DEAD)
 		return;
-	c = ARRAY_ITEM(&clients, cdata->client);
 
 	if ((u_int) idx > ARRAY_LENGTH(&sessions) - 1)
 		return;
@@ -121,7 +120,7 @@ cmd_choose_session_callback(void *data, int idx)
 	if (cmd_string_parse(template, &cmdlist, &cause) != 0) {
 		if (cause != NULL) {
 			*cause = toupper((u_char) *cause);
-			status_message_set(c, "%s", cause);
+			status_message_set(cdata->client, "%s", cause);
 			xfree(cause);
 		}
 		xfree(template);
@@ -130,7 +129,7 @@ cmd_choose_session_callback(void *data, int idx)
 	xfree(template);
 
 	ctx.msgdata = NULL;
-	ctx.curclient = c;
+	ctx.curclient = cdata->client;
 
 	ctx.error = key_bindings_error;
 	ctx.print = key_bindings_print;
@@ -147,6 +146,7 @@ cmd_choose_session_free(void *data)
 {
 	struct cmd_choose_session_data	*cdata = data;
 
+	cdata->client->references--;
 	xfree(cdata->template);
 	xfree(cdata);
 }
diff --git a/cmd-choose-window.c b/cmd-choose-window.c
index ddc8ecb6..43a24585 100644
--- a/cmd-choose-window.c
+++ b/cmd-choose-window.c
@@ -43,8 +43,8 @@ const struct cmd_entry cmd_choose_window_entry = {
 };
 
 struct cmd_choose_window_data {
-	u_int		 client;
-	u_int		 session;
+	struct client	*client;
+	struct session	*session;
 	char   		*template;
 };
 
@@ -107,13 +107,14 @@ cmd_choose_window_exec(struct cmd *self, struct cmd_ctx *ctx)
 	}
 
 	cdata = xmalloc(sizeof *cdata);
-	if (session_index(s, &cdata->session) != 0)
-		fatalx("session not found");
 	if (data->arg != NULL)
 		cdata->template = xstrdup(data->arg);
 	else
 		cdata->template = xstrdup("select-window -t '%%'");
-	cdata->client = server_client_index(ctx->curclient);
+	cdata->session = s;
+	cdata->session->references++;
+	cdata->client = ctx->curclient;
+	cdata->client->references++;
 
 	window_choose_ready(wl->window->active, 
 	    cur, cmd_choose_window_callback, cmd_choose_window_free, cdata);
@@ -125,31 +126,27 @@ void
 cmd_choose_window_callback(void *data, int idx)
 {
 	struct cmd_choose_window_data	*cdata = data;
-	struct client			*c;
-	struct session			*s;
 	struct cmd_list			*cmdlist;
 	struct cmd_ctx			 ctx;
 	char				*target, *template, *cause;
 
 	if (idx == -1)
 		return;
-	if (cdata->client > ARRAY_LENGTH(&clients) - 1)
+	if (cdata->client->flags & CLIENT_DEAD)
+		return;	
+	if (cdata->session->flags & SESSION_DEAD)
 		return;
-	c = ARRAY_ITEM(&clients, cdata->client);
-	if (cdata->session > ARRAY_LENGTH(&sessions) - 1)
-		return;
-	s = ARRAY_ITEM(&sessions, cdata->session);
-	if (c->session != s)
+	if (cdata->client->session != cdata->session)
 		return;
 
-	xasprintf(&target, "%s:%d", s->name, idx);
+	xasprintf(&target, "%s:%d", cdata->session->name, idx);
 	template = cmd_template_replace(cdata->template, target, 1);
 	xfree(target);
 
 	if (cmd_string_parse(template, &cmdlist, &cause) != 0) {
 		if (cause != NULL) {
 			*cause = toupper((u_char) *cause);
-			status_message_set(c, "%s", cause);
+			status_message_set(cdata->client, "%s", cause);
 			xfree(cause);
 		}
 		xfree(template);
@@ -158,7 +155,7 @@ cmd_choose_window_callback(void *data, int idx)
 	xfree(template);
 
 	ctx.msgdata = NULL;
-	ctx.curclient = c;
+	ctx.curclient = cdata->client;
 
 	ctx.error = key_bindings_error;
 	ctx.print = key_bindings_print;
@@ -175,6 +172,8 @@ cmd_choose_window_free(void *data)
 {
 	struct cmd_choose_window_data	*cdata = data;
 
+	cdata->session->references--;
+	cdata->client->references--;
 	xfree(cdata->template);
 	xfree(cdata);
 }
diff --git a/cmd-server-info.c b/cmd-server-info.c
index 14212478..48ea3707 100644
--- a/cmd-server-info.c
+++ b/cmd-server-info.c
@@ -91,9 +91,10 @@ cmd_server_info_exec(unused struct cmd *self, struct cmd_ctx *ctx)
 			continue;
 
 		ctx->print(ctx, "%2d: %s (%d, %d): %s [%ux%u %s] "
-		    "[flags=0x%x/0x%x]", i, c->tty.path, c->ibuf.fd, c->tty.fd,
-		    c->session->name, c->tty.sx, c->tty.sy, c->tty.termname,
-		    c->flags, c->tty.flags);
+		    "[flags=0x%x/0x%x, references=%u]", i, c->tty.path,
+		    c->ibuf.fd, c->tty.fd, c->session->name,
+		    c->tty.sx, c->tty.sy, c->tty.termname, c->flags, 
+		    c->tty.flags, c->references);
 	}
 	ctx->print(ctx, "%s", "");
 
@@ -109,8 +110,9 @@ cmd_server_info_exec(unused struct cmd *self, struct cmd_ctx *ctx)
 		*strchr(tim, '\n') = '\0';
 
 		ctx->print(ctx, "%2u: %s: %u windows (created %s) [%ux%u] "
-		    "[flags=0x%x]", i, s->name, winlink_count(&s->windows),
-		    tim, s->sx, s->sy, s->flags);
+		    "[flags=0x%x, references=%u]", i, s->name,
+		    winlink_count(&s->windows), tim, s->sx, s->sy, s->flags,
+		    s->references);
 		RB_FOREACH(wl, winlinks, &s->windows) {
 			w = wl->window;
 			ctx->print(ctx, "%4u: %s [%ux%u] [flags=0x%x, "
diff --git a/server.c b/server.c
index 09c412d5..c8b96368 100644
--- a/server.c
+++ b/server.c
@@ -43,6 +43,7 @@
 
 /* Client list. */
 struct clients	 clients;
+struct clients	 dead_clients;
 
 void		 server_create_client(int);
 int		 server_create_socket(void);
@@ -61,6 +62,7 @@ int		 server_check_window_activity(struct session *,
 		      struct window *);
 int		 server_check_window_content(struct session *, struct window *,
 		      struct window_pane *);
+void		 server_clean_dead(void);
 void		 server_lost_client(struct client *);
 void	 	 server_check_window(struct window *);
 void		 server_check_redraw(struct client *);
@@ -85,6 +87,7 @@ server_create_client(int fd)
 		fatal("fcntl failed");
 
 	c = xcalloc(1, sizeof *c);
+	c->references = 0;
 	imsg_init(&c->ibuf, fd);
 
 	ARRAY_INIT(&c->prompt_hdata);
@@ -162,7 +165,9 @@ server_start(char *path)
 
 	ARRAY_INIT(&windows);
 	ARRAY_INIT(&clients);
+	ARRAY_INIT(&dead_clients);
 	ARRAY_INIT(&sessions);
+	ARRAY_INIT(&dead_sessions);
 	mode_key_init_trees();
 	key_bindings_init();
 	utf8_build();
@@ -344,6 +349,9 @@ server_main(int srv_fd)
 
 		/* Collect any unset key bindings. */
 		key_bindings_clean();
+
+		/* Collect dead clients and sessions. */
+		server_clean_dead();
 		
 		/*
 		 * If we have no sessions and clients left, let's get out
@@ -948,11 +956,45 @@ server_lost_client(struct client *c)
 
 	close(c->ibuf.fd);
 	imsg_clear(&c->ibuf);
-	xfree(c);
+
+	for (i = 0; i < ARRAY_LENGTH(&dead_clients); i++) {
+		if (ARRAY_ITEM(&dead_clients, i) == NULL) {
+			ARRAY_SET(&dead_clients, i, c);
+			break;
+		}
+	}
+	if (i == ARRAY_LENGTH(&dead_clients))
+		ARRAY_ADD(&dead_clients, c);
+	c->flags |= CLIENT_DEAD;
 
 	recalculate_sizes();
 }
 
+/* Free dead, unreferenced clients and sessions. */
+void
+server_clean_dead(void)
+{
+	struct session	*s;
+	struct client	*c;
+	u_int		 i;
+
+	for (i = 0; i < ARRAY_LENGTH(&dead_sessions); i++) {
+		s = ARRAY_ITEM(&dead_sessions, i);
+		if (s == NULL || s->references != 0)
+			continue;
+		ARRAY_SET(&dead_sessions, i, NULL);
+		xfree(s);
+	}
+
+	for (i = 0; i < ARRAY_LENGTH(&dead_clients); i++) {
+		c = ARRAY_ITEM(&dead_clients, i);
+		if (c == NULL || c->references != 0)
+			continue;
+		ARRAY_SET(&dead_clients, i, NULL);
+		xfree(c);
+	}
+}
+
 /* Handle window data. */
 void
 server_handle_window(struct window *w, struct window_pane *wp)
diff --git a/session.c b/session.c
index 55d38c80..4e5ac83e 100644
--- a/session.c
+++ b/session.c
@@ -28,6 +28,7 @@
 
 /* Global session list. */
 struct sessions	sessions;
+struct sessions dead_sessions;
 
 struct winlink *session_next_activity(struct session *, struct winlink *);
 struct winlink *session_previous_activity(struct session *, struct winlink *);
@@ -121,14 +122,19 @@ session_create(const char *name, const char *cmd, const char *cwd,
 	u_int		 i;
 
 	s = xmalloc(sizeof *s);
+	s->references = 0;
 	s->flags = 0;
+
 	if (gettimeofday(&s->tv, NULL) != 0)
 		fatal("gettimeofday");
+
 	s->curw = NULL;
 	SLIST_INIT(&s->lastw);
 	RB_INIT(&s->windows);
 	SLIST_INIT(&s->alerts);
+
 	paste_init_stack(&s->buffers);
+
 	options_init(&s->options, &global_s_options);
 	environ_init(&s->environ);
 	if (env != NULL)
@@ -187,7 +193,16 @@ session_destroy(struct session *s)
 		winlink_remove(&s->windows, RB_ROOT(&s->windows));
 
 	xfree(s->name);
-	xfree(s);
+	
+	for (i = 0; i < ARRAY_LENGTH(&dead_sessions); i++) {
+		if (ARRAY_ITEM(&dead_sessions, i) == NULL) {
+			ARRAY_SET(&dead_sessions, i, s);
+			break;
+		}
+	}
+	if (i == ARRAY_LENGTH(&dead_sessions))
+		ARRAY_ADD(&dead_sessions, s);
+	s->flags |= SESSION_DEAD;
 }
 
 /* Find session index. */
diff --git a/tmux.h b/tmux.h
index 4057fe8b..7b725b00 100644
--- a/tmux.h
+++ b/tmux.h
@@ -812,11 +812,14 @@ struct session {
 	SLIST_HEAD(, session_alert) alerts;
 
 #define SESSION_UNATTACHED 0x1	/* not attached to any clients */
+#define SESSION_DEAD 0x2
 	int		 flags;
 
 	struct termios   tio;
 
 	struct environ	 environ;
+
+	int		 references;
 };
 ARRAY_DECL(sessions, struct session *);
 
@@ -939,6 +942,7 @@ struct client {
 #define CLIENT_SUSPENDED 0x40
 #define CLIENT_BAD 0x80
 #define CLIENT_IDENTIFY 0x100
+#define CLIENT_DEAD 0x200
 	int		 flags;
 
 	struct timeval	 identify_timer;
@@ -963,6 +967,8 @@ struct client {
 	struct mode_key_data prompt_mdata;
 
 	struct session	*session;
+
+	int		 references;
 };
 ARRAY_DECL(clients, struct client *);
 
@@ -1428,6 +1434,7 @@ const char *key_string_lookup_key(int);
 
 /* server.c */
 extern struct clients clients;
+extern struct clients dead_clients;
 int	 server_client_index(struct client *);
 int	 server_start(char *);
 
@@ -1702,6 +1709,7 @@ char 		*default_window_name(struct window *);
 
 /* session.c */
 extern struct sessions sessions;
+extern struct sessions dead_sessions;
 void	 session_alert_add(struct session *, struct window *, int);
 void	 session_alert_cancel(struct session *, struct winlink *);
 int	 session_alert_has(struct session *, struct winlink *, int);