diff --git a/FileLogger.cs b/FileLogger.cs
index 52278cb..007d368 100644
--- a/FileLogger.cs
+++ b/FileLogger.cs
@@ -50,10 +50,14 @@ namespace ln.logging
             {
                 throw new ObjectDisposedException("FileLogger has already been disposed");
             }
-            foreach (String line in lines)
+
+            lock (writer)
             {
-                writer.WriteLine(line);
-                writer.Flush();
+                foreach (String line in lines)
+                {
+                    writer.WriteLine(line);
+                    writer.Flush();
+                }
             }
         }