diff --git a/pl/signals.yap b/pl/signals.yap
index 3e529e969..606273eb3 100644
--- a/pl/signals.yap
+++ b/pl/signals.yap
@@ -249,6 +249,12 @@ alarm(Interval, Goal, Left) :-
 	integer(Interval), !,
 	on_signal(sig_alarm, _, Goal),
 	'$alarm'(Interval, 0, Left, _).
+alarm(Number, Goal, Left) :-
+	float(Number), !,
+	Secs is integer(Number),
+	USecs is integer((Number-Secs)*1000000) mod 1000000,
+	on_signal(sig_alarm, _, Goal),
+	'$alarm'(Interval, 0, Left, _).
 alarm(Interval.USecs, Goal, Left.LUSecs) :-
 	on_signal(sig_alarm, _, Goal),
 	'$alarm'(Interval, USecs, Left, LUSecs).