diff --git a/handlers/downtimes.go b/handlers/downtimes.go
index a409b535..264a5b70 100644
--- a/handlers/downtimes.go
+++ b/handlers/downtimes.go
@@ -108,6 +108,12 @@ func apiCreateDowntimeHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	if downtime.CheckOverlapping() {
+		err := fmt.Errorf("downtime interval overlapping error")
+		sendErrorJson(err, w, r)
+		return
+	}
+
 	s, err := services.FindFirstFromDB(downtime.ServiceId)
 	if err != nil {
 		sendErrorJson(err, w, r)
diff --git a/types/downtimes/database.go b/types/downtimes/database.go
index ab4e237f..47b8f35c 100644
--- a/types/downtimes/database.go
+++ b/types/downtimes/database.go
@@ -74,6 +74,20 @@ func FindLatestDowntimeOfService(service int64) Downtime {
 	return downtime
 }
 
+func (c *Downtime) CheckOverlapping() bool {
+	var downtimes []Downtime
+	q := db.Where("service = ?", c.ServiceId)
+	q = q.Where("\"end\" IS NULL or \"end\" >= ?", c.Start)
+	if c.End != nil {
+		q = q.Where("start <= ?", c.End)
+	}
+	q = q.Find(&downtimes)
+	if len(downtimes) > 0 {
+		return true
+	}
+	return false
+}
+
 func FindAll(vars map[string]string) (*[]Downtime, error) {
 	var downtime []Downtime
 	var start time.Time