diff --git a/cmd-resize-pane.c b/cmd-resize-pane.c
new file mode 100644
index 00000000..53b2de52
--- /dev/null
+++ b/cmd-resize-pane.c
@@ -0,0 +1,151 @@
+/* $Id: cmd-resize-pane.c,v 1.1 2009-04-30 06:01:35 nicm Exp $ */
+
+/*
+ * Copyright (c) 2009 Nicholas Marriott <nicm@users.sourceforge.net>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
+ * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
+ * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+
+#include <stdlib.h>
+
+#include "tmux.h"
+
+/*
+ * Increase or decrease pane size.
+ */
+
+void	cmd_resize_pane_init(struct cmd *, int);
+int	cmd_resize_pane_exec(struct cmd *, struct cmd_ctx *);
+
+const struct cmd_entry cmd_resize_pane_entry = {
+	"resize-pane", "resizep",
+	CMD_PANE_WINDOW_USAGE "[-DU] [adjustment]",
+	CMD_ARG01|CMD_UPPERUFLAG|CMD_UPPERDFLAG,
+	cmd_resize_pane_init,
+	cmd_pane_parse,
+	cmd_resize_pane_exec,
+       	cmd_pane_send,
+	cmd_pane_recv,
+	cmd_pane_free,
+	cmd_pane_print
+};
+
+void
+cmd_resize_pane_init(struct cmd *self, int key)
+{
+	struct cmd_pane_data	*data;
+
+	cmd_pane_init(self, key);
+	data = self->data;
+
+	if (key == KEYC_ADDCTL(KEYC_DOWN))
+		data->flags |= CMD_UPPERDFLAG;
+
+	if (key == KEYC_ADDESC(KEYC_UP))
+		data->arg = xstrdup("5");
+	if (key == KEYC_ADDESC(KEYC_DOWN)) {
+		data->flags |= CMD_UPPERDFLAG;
+		data->arg = xstrdup("5");
+	}
+}
+
+int
+cmd_resize_pane_exec(struct cmd *self, struct cmd_ctx *ctx)
+{
+	struct cmd_pane_data	*data = self->data;
+	struct winlink		*wl;
+	const char	       	*errstr;
+	struct window_pane	*wp, *wq;
+	u_int			 adjust;
+	
+	if ((wl = cmd_find_window(ctx, data->target, NULL)) == NULL)
+		return (-1);
+	if (wl->window->layout != 0) {
+		ctx->error(ctx, "window not in manual layout");
+		return (-1);
+	}
+	if (data->pane == -1)
+		wp = wl->window->active;
+	else {
+		wp = window_pane_at_index(wl->window, data->pane);
+		if (wp == NULL) {
+			ctx->error(ctx, "no pane: %d", data->pane);
+			return (-1);
+		}
+	}
+
+	if (data->arg == NULL)
+		adjust = 1;
+	else {
+		adjust = strtonum(data->arg, 1, INT_MAX, &errstr);
+		if (errstr != NULL) {
+			ctx->error(ctx, "adjustment %s: %s", errstr, data->arg);
+			return (-1);
+		}
+	}
+
+	if (data->flags & CMD_UPPERDFLAG) {
+		/*
+		 * If this is not the last window, keep trying to increase size
+		 * and remove it from the next windows. If it is the last, do
+		 * so on the previous window.
+		 */
+		if (TAILQ_NEXT(wp, entry) == NULL) {
+			if (wp == TAILQ_FIRST(&wl->window->panes)) {
+				/* Only one pane. */
+				return (0);
+			}
+			wp = TAILQ_PREV(wp, window_panes, entry);
+		}
+		while (adjust-- > 0) {
+			wq = wp;
+			while ((wq = TAILQ_NEXT(wq, entry)) != NULL) {
+				if (wq->sy <= PANE_MINIMUM)
+					continue;
+				window_pane_resize(wq, wq->sx, wq->sy - 1);
+				break;
+			}
+			if (wq == NULL)
+				break;
+		window_pane_resize(wp, wp->sx, wp->sy + 1);
+		}
+	} else {
+		/*
+		 * If this is not the last window, keep trying to reduce size
+		 * and add to the following window. If it is the last, do so on
+		 * the previous window.
+		 */
+		wq = TAILQ_NEXT(wp, entry);
+		if (wq == NULL) {
+			if (wp == TAILQ_FIRST(&wl->window->panes)) {
+				/* Only one pane. */
+				return (0);
+			}
+			wq = wp;
+			wp = TAILQ_PREV(wq, window_panes, entry);
+		}
+		while (adjust-- > 0) {
+			if (wp->sy <= PANE_MINIMUM)
+				break;
+			window_pane_resize(wq, wq->sx, wq->sy + 1);
+			window_pane_resize(wp, wp->sx, wp->sy - 1);
+		}
+	}
+	window_update_panes(wl->window);
+
+	server_redraw_window(wl->window);
+
+	return (0);
+}