diff --git a/source.go b/source.go
index 3acf6b8..94b7ee5 100644
--- a/source.go
+++ b/source.go
@@ -86,7 +86,7 @@ func (l Source) MarshalText() ([]byte, error) {
 }
 
 func (l Source) MarshalJSON() ([]byte, error) {
-	return fmt.Appendf([]byte{}, `{"file":"%s","line":%d,"func":"%s"}`, l.File, l.Line, l.Func), nil
+	return fmt.Appendf([]byte{}, `{"file":%q,"line":%d,"func":"%s"}`, l.File, l.Line, l.Func), nil
 }
 
 func errSourceField(skip, mframe int) field.Field {
diff --git a/source_test.go b/source_test.go
new file mode 100644
index 0000000..8587184
--- /dev/null
+++ b/source_test.go
@@ -0,0 +1,23 @@
+package log_test
+
+import (
+	"encoding/json"
+	"testing"
+
+	"gitoa.ru/go-4devs/log"
+)
+
+func TestSource_MarshalJSON(t *testing.T) {
+	t.Parallel()
+
+	src := log.Source{
+		Func: "fn name",
+		File: `file " \n name`,
+		Line: 42,
+	}
+
+	data, err := json.Marshal(src)
+	if err != nil || len(data) == 0 || string(data) != `{"file":"file \" \\n name","line":42,"func":"fn name"}` {
+		t.Fatalf("failed marshal: err=%v, data=%v", err, string(data))
+	}
+}