diff --git a/cluster.go b/cluster.go
index 07de993..6aacd03 100644
--- a/cluster.go
+++ b/cluster.go
@@ -627,6 +627,8 @@ func (opt *ClusterOptions) init() {
 }
 
 func (opt *ClusterOptions) clientOptions() *Options {
+	const disableIdleCheck = -1
+
 	return &Options{
 		Password: opt.Password,
 		ReadOnly: opt.ReadOnly,
@@ -640,5 +642,6 @@ func (opt *ClusterOptions) clientOptions() *Options {
 		IdleTimeout: opt.IdleTimeout,
 
 		// IdleCheckFrequency is not copied to disable reaper
+		IdleCheckFrequency: disableIdleCheck,
 	}
 }
diff --git a/options.go b/options.go
index 3f9a462..bfe2e8a 100644
--- a/options.go
+++ b/options.go
@@ -53,6 +53,7 @@ type Options struct {
 	IdleTimeout time.Duration
 	// Frequency of idle checks.
 	// Default is 1 minute.
+	// When minus value is set, then idle check is disabled.
 	IdleCheckFrequency time.Duration
 
 	// Enables read only queries on slave nodes.