diff --git a/viper.go b/viper.go
index 46b1a85..bf1d442 100644
--- a/viper.go
+++ b/viper.go
@@ -1405,9 +1405,9 @@ func InConfig(key string) bool { return v.InConfig(key) }
 
 func (v *Viper) InConfig(key string) bool {
 	// if the requested key is an alias, then return the proper key
-	key = v.realKey(key)
+	key = v.realKey(strings.ToLower(key))
 
-	_, exists := v.config[key]
+	_, exists := v.config[strings.ToLower(key)]
 	return exists
 }
 
diff --git a/viper_test.go b/viper_test.go
index 4192748..6caa0c9 100644
--- a/viper_test.go
+++ b/viper_test.go
@@ -382,6 +382,7 @@ func TestUnmarshaling(t *testing.T) {
 
 	unmarshalReader(r, v.config)
 	assert.True(t, InConfig("name"))
+	assert.True(t, InConfig("NAME"))
 	assert.False(t, InConfig("state"))
 	assert.Equal(t, "steve", Get("name"))
 	assert.Equal(t, []interface{}{"skateboarding", "snowboarding", "go"}, Get("hobbies"))