diff --git a/config_test.go b/config_test.go
index 2a8258d..1591c7a 100644
--- a/config_test.go
+++ b/config_test.go
@@ -134,6 +134,13 @@ type testCfg struct {
 			Uint8Field  uint8
 		}
 	}
+	SecondNestedStruct struct {
+		StringField string
+		StructField struct {
+			StringField string
+		}
+		SecondStringField string
+	}
 }
 
 func (p *pFull) Provide(config interface{}) error {
@@ -156,6 +163,21 @@ func (p *pFull) Provide(config interface{}) error {
 				NestedInt16: 321,
 			},
 		},
+		SecondNestedStruct: struct {
+			StringField string
+			StructField struct {
+				StringField string
+			}
+			SecondStringField string
+		}{
+			StringField: "nested-123",
+			StructField: struct {
+				StringField string
+			}{
+				StringField: "inner-nested",
+			},
+			SecondStringField: "nested-123",
+		},
 	}
 
 	parse(config, &cfg)
diff --git a/env.go b/env.go
index c00f9cb..5e6fa72 100644
--- a/env.go
+++ b/env.go
@@ -52,7 +52,7 @@ func provide(prefix string, config reflect.Value) error {
 }
 
 func parseValue(prefix string, vField reflect.Value, tField reflect.StructField) error {
-	if prefix != "" {
+	if prefix != "" && !strings.HasSuffix(prefix, "_") {
 		prefix = strings.ToUpper(prefix) + "_"
 	}
 
diff --git a/env_test.go b/env_test.go
index 1e0cb1f..9689df7 100644
--- a/env_test.go
+++ b/env_test.go
@@ -69,6 +69,15 @@ func TestEnvConfigWithoutPrefix(t *testing.T) {
 	if cfg.NestedStruct.AnotherLevel.Uint8Field != uint8Filed {
 		t.Errorf("Value is '%d', but %d expected", cfg.NestedStruct.AnotherLevel.Uint8Field, uint8Filed)
 	}
+	if cfg.SecondNestedStruct.StringField != nestedString {
+		t.Errorf("Value is '%s', but %q expected", cfg.SecondNestedStruct.StringField, nestedString)
+	}
+	if cfg.SecondNestedStruct.SecondStringField != nestedString {
+		t.Errorf("Value is '%s', but %q expected", cfg.SecondNestedStruct.SecondStringField, nestedString)
+	}
+	if cfg.SecondNestedStruct.StructField.StringField != nestedString {
+		t.Errorf("Value is '%s', but %q expected", cfg.SecondNestedStruct.StructField.StringField, nestedString)
+	}
 }
 
 func TestEnvConfigEmptyString(t *testing.T) {
@@ -158,4 +167,7 @@ func setUpEnv(prefix string) {
 	_ = os.Setenv(p+"NESTEDSTRUCT_FLOAT32FIELD", fmt.Sprintf("%f", float32Field))
 	_ = os.Setenv(p+"NESTEDSTRUCT_ANOTHERLEVEL_NESTEDINT16", strconv.Itoa(nestedInt16))
 	_ = os.Setenv(p+"NESTEDSTRUCT_ANOTHERLEVEL_UINT8FIELD", strconv.Itoa(uint8Filed))
+	_ = os.Setenv(p+"SECONDNESTEDSTRUCT_STRINGFIELD", nestedString)
+	_ = os.Setenv(p+"SECONDNESTEDSTRUCT_STRUCTFIELD_STRINGFIELD", nestedString)
+	_ = os.Setenv(p+"SECONDNESTEDSTRUCT_SECONDSTRINGFIELD", nestedString)
 }