diff --git a/prometheus/process_collector.go b/prometheus/process_collector.go
index efbc3ea..62a4e7a 100644
--- a/prometheus/process_collector.go
+++ b/prometheus/process_collector.go
@@ -140,6 +140,8 @@ func (c *processCollector) Describe(ch chan<- *Desc) {
 	ch <- c.maxVsize
 	ch <- c.rss
 	ch <- c.startTime
+	ch <- c.inBytes
+	ch <- c.outBytes
 }
 
 // Collect returns the current state of all metrics of the collector.