diff --git c/config.def.h w/config.def.h
index 7ee7f9d..176294a 100644
--- c/config.def.h
+++ w/config.def.h
@@ -21,6 +21,9 @@ static const char *colors[][3]      = {
 /* tagging */
 static const char *tags[] = { "1", "2", "3", "4", "5", "6", "7", "8", "9" };
 
+/* Lockfile */
+static char lockfile[] = "/tmp/dwm.lock";
+
 static const Rule rules[] = {
 	/* xprop(1):
 	 *	WM_CLASS(STRING) = instance, class
diff --git c/dwm.c w/dwm.c
index b1c07e8..55925bd 100644
--- c/dwm.c
+++ w/dwm.c
@@ -27,6 +27,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/wait.h>
@@ -1262,7 +1263,24 @@ propertynotify(XEvent *e)
 void
 quit(const Arg *arg)
 {
-	running = 0;
+	FILE *fd = NULL;
+	struct stat filestat;
+
+	if ((fd = fopen(lockfile, "r")) && stat(lockfile, &filestat) == 0) {
+		fclose(fd);
+
+		if (filestat.st_ctime <= time(NULL)-2)
+			remove(lockfile);
+	}
+
+	if ((fd = fopen(lockfile, "r")) != NULL) {
+		fclose(fd);
+		remove(lockfile);
+		running = 0;
+	} else {
+		if ((fd = fopen(lockfile, "a")) != NULL)
+			fclose(fd);
+	}
 }
 
 Monitor *