diff --git a/envconf.go b/envconf.go
index cc44d47..e22b710 100644
--- a/envconf.go
+++ b/envconf.go
@@ -79,7 +79,7 @@ func NewConfig() *Config {
 							lmiddle := splitted[count]
 							rmiddle := splitted[count+1]
 							right = strings.Trim(strings.Join(splitted[count+2:], "_"), "_")
-							if len(config.mapMapEnv[left][lmiddle][rmiddle]) == 0 {
+							if len(config.mapMapMapEnv[left][lmiddle][rmiddle]) == 0 {
 								config.mapMapMapEnv[left][lmiddle][rmiddle] = make(map[string]string)
 							}
 							if left != "" && lmiddle != "" && rmiddle != "" && right != "" {