diff --git a/.gitignore b/.gitignore
index 8c0f4ef..27626c8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 postfix_exporter
+.idea/
diff --git a/postfix_exporter.go b/postfix_exporter.go
index 18df8c7..eb2b679 100644
--- a/postfix_exporter.go
+++ b/postfix_exporter.go
@@ -111,6 +111,12 @@ func CollectTextualShowqFromReader(file io.Reader, ch chan<- prometheus.Metric)
 		},
 		[]string{"queue"})
 
+	// Initialize all queue buckets to zero.
+	for _, q := range []string{"active", "hold", "other"} {
+		sizeHistogram.WithLabelValues(q)
+		ageHistogram.WithLabelValues(q)
+	}
+
 	now := time.Now()
 	location, _ := time.LoadLocation("Local")
 	for scanner.Scan() {
@@ -192,6 +198,12 @@ func CollectBinaryShowqFromReader(file io.Reader, ch chan<- prometheus.Metric) e
 		},
 		[]string{"queue"})
 
+	// Initialize all queue buckets to zero.
+	for _, q := range []string{"active", "deferred", "hold", "incoming", "maildrop"} {
+		sizeHistogram.WithLabelValues(q)
+		ageHistogram.WithLabelValues(q)
+	}
+
 	now := float64(time.Now().UnixNano()) / 1e9
 	queue := "unknown"
 	for scanner.Scan() {