diff --git a/config.def.h b/config.def.h
index 9855e21..d01bd38 100644
--- a/config.def.h
+++ b/config.def.h
@@ -10,3 +10,6 @@ static const char *colorname[NUMCOLS] = {

 /* treat a cleared input like a wrong password (color) */
 static const int failonclear = 1;
+
+/* time in seconds before the monitor shuts down */
+static const int monitortime = 20;
diff --git a/slock.c b/slock.c
index d2f0886..f65a43b 100644
--- a/slock.c
+++ b/slock.c
@@ -15,6 +15,7 @@
 #include <unistd.h>
 #include <sys/types.h>
 #include <X11/extensions/Xrandr.h>
+#include <X11/extensions/dpms.h>
 #include <X11/keysym.h>
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
@@ -306,6 +307,7 @@ main(int argc, char **argv) {
 	const char *hash;
 	Display *dpy;
 	int s, nlocks, nscreens;
+	CARD16 standby, suspend, off;

 	ARGBEGIN {
 	case 'v':
@@ -366,6 +368,20 @@ main(int argc, char **argv) {
 	if (nlocks != nscreens)
 		return 1;

+	/* DPMS magic to disable the monitor */
+	if (!DPMSCapable(dpy))
+		die("slock: DPMSCapable failed\n");
+	if (!DPMSEnable(dpy))
+		die("slock: DPMSEnable failed\n");
+	if (!DPMSGetTimeouts(dpy, &standby, &suspend, &off))
+		die("slock: DPMSGetTimeouts failed\n");
+	if (!standby || !suspend || !off)
+		die("slock: at least one DPMS variable is zero\n");
+	if (!DPMSSetTimeouts(dpy, monitortime, monitortime, monitortime))
+		die("slock: DPMSSetTimeouts failed\n");
+
+	XSync(dpy, 0);
+
 	/* run post-lock command */
 	if (argc > 0) {
 		switch (fork()) {
@@ -383,5 +399,9 @@ main(int argc, char **argv) {
 	/* everything is now blank. Wait for the correct password */
 	readpw(dpy, &rr, locks, nscreens, hash);

+	/* reset DPMS values to inital ones */
+	DPMSSetTimeouts(dpy, standby, suspend, off);
+	XSync(dpy, 0);
+
 	return 0;
 }