diff --git a/top/top.c b/top/top.c
index 73598e26..db0c6411 100644
--- a/top/top.c
+++ b/top/top.c
@@ -97,7 +97,7 @@ static float       Cpu_pmax;
 static const char *Cpu_States_fmts;
 
         /* Specific process id monitoring support */
-static pid_t Monpids [MONPIDMAX] = { 0 };
+static pid_t Monpids [MONPIDMAX+1] = { 0 };
 static int   Monpidsidx = 0;
 
         /* Current screen dimensions.