diff --git a/level.go b/level.go
index 98dd191..5123f8e 100644
--- a/level.go
+++ b/level.go
@@ -66,6 +66,7 @@ type LeveledBackend interface {
 }
 
 type moduleLeveled struct {
+	sync.RWMutex
 	levels    map[string]Level
 	backend   Backend
 	formatter Formatter
@@ -88,6 +89,8 @@ func AddModuleLevel(backend Backend) LeveledBackend {
 
 // GetLevel returns the log level for the given module.
 func (l *moduleLeveled) GetLevel(module string) Level {
+	l.RLock()
+	defer l.RUnlock()
 	level, exists := l.levels[module]
 	if exists == false {
 		level, exists = l.levels[""]
@@ -101,6 +104,8 @@ func (l *moduleLeveled) GetLevel(module string) Level {
 
 // SetLevel sets the log level for the given module.
 func (l *moduleLeveled) SetLevel(level Level, module string) {
+	l.Lock()
+	defer l.Unlock()
 	l.levels[module] = level
 }
 
diff --git a/logger_test.go b/logger_test.go
index b9f7fe7..470e39b 100644
--- a/logger_test.go
+++ b/logger_test.go
@@ -60,3 +60,17 @@ func TestPrivateBackend(t *testing.T) {
 		t.Error("logged to defaultBackend:", MemoryRecordN(privateBackend, 0))
 	}
 }
+
+func TestConcurrency(t *testing.T) {
+	logger := MustGetLogger("test")
+	go func() {
+		for i := 0; i < 1000; i++ {
+			SetLevel(Level(DEBUG), "test")
+		}
+	}()
+
+	for i := 0; i < 1000; i++ {
+		logger.Info("")
+	}
+}
+