diff --git a/envconf.go b/envconf.go
index 07629c3..5465e9f 100644
--- a/envconf.go
+++ b/envconf.go
@@ -44,7 +44,7 @@ func NewConfig() *Config {
 		if len(splitted) == 2 {
 			key := cleanKey(splitted[0])
 			val := splitted[1]
-			splitted = strings.Split(key, "_")
+			splitted = append(strings.Split(key, "_"), "", "", "")
 			if unicode.IsLetter(getFirstRune(key)) {
 				var entry cEntry
 				entry.value = val
@@ -54,15 +54,16 @@ func NewConfig() *Config {
 				config.env[key] = entry
 				if len(splitted) > 1 {
 					for count, _ := range splitted {
-						left := strings.Join(splitted[:count], "_")
-						right := strings.Join(splitted[count:], "_")
-						if len(config.mapEnv[left]) == 0 {
-							config.mapEnv[left] = make(map[string]string)
-							config.mapMapEnv[left] = make(map[string]map[string]string)
-							config.mapMapMapEnv[left] = make(map[string]map[string]map[string]string)
-						}
-						config.mapEnv[left][right] = key
-						if count < len(splitted)-1 {
+						if count < len(splitted)-3 {
+							left := strings.Join(splitted[:count], "_")
+							right := strings.Join(splitted[count:], "_")
+							if len(config.mapEnv[left]) == 0 {
+								config.mapEnv[left] = make(map[string]string)
+								config.mapMapEnv[left] = make(map[string]map[string]string)
+								config.mapMapMapEnv[left] = make(map[string]map[string]map[string]string)
+							}
+							config.mapEnv[left][right] = key
+
 							middle := splitted[count]
 							right = strings.Join(splitted[count+1:], "_")
 							if len(config.mapMapEnv[left][middle]) == 0 {
@@ -70,15 +71,14 @@ func NewConfig() *Config {
 								config.mapMapMapEnv[left][middle] = make(map[string]map[string]string)
 							}
 							config.mapMapEnv[left][middle][right] = key
-							if count < len(splitted)-2 {
-								lmiddle := splitted[count]
-								rmiddle := splitted[count+1]
-								right = strings.Join(splitted[count+2:], "_")
-								if len(config.mapMapEnv[left][lmiddle][rmiddle]) == 0 {
-									config.mapMapMapEnv[left][lmiddle][rmiddle] = make(map[string]string)
-								}
-								config.mapMapMapEnv[left][lmiddle][rmiddle][right] = key
+
+							lmiddle := splitted[count]
+							rmiddle := splitted[count+1]
+							right = strings.Join(splitted[count+2:], "_")
+							if len(config.mapMapEnv[left][lmiddle][rmiddle]) == 0 {
+								config.mapMapMapEnv[left][lmiddle][rmiddle] = make(map[string]string)
 							}
+							config.mapMapMapEnv[left][lmiddle][rmiddle][right] = key
 						}
 					}
 				}