diff --git a/upup/cmd/cloudup/main.go b/upup/cmd/cloudup/main.go
index 95a3f82524..0837740cbf 100644
--- a/upup/cmd/cloudup/main.go
+++ b/upup/cmd/cloudup/main.go
@@ -57,6 +57,9 @@ func main() {
 	nodeSize := ""
 	flag.StringVar(&nodeSize, "node-size", nodeSize, "Set instance size for nodes")
 
+	masterSize := ""
+	flag.StringVar(&masterSize, "master-size", masterSize, "Set instance size for masters")
+
 	nodeCount := 0
 	flag.IntVar(&nodeCount, "node-count", nodeCount, "Set the number of nodes")
 
@@ -79,6 +82,10 @@ func main() {
 		config.NodeCount = nodeCount
 	}
 
+	if masterSize != "" {
+		config.MasterMachineType = masterSize
+	}
+
 	if dnsZone != "" {
 		config.DNSZone = dnsZone
 	}