diff --git a/include/boost/thread/thread.hpp b/include/boost/thread/thread.hpp
index 5666bb5c..92b1b34d 100644
--- a/include/boost/thread/thread.hpp
+++ b/include/boost/thread/thread.hpp
@@ -70,7 +70,7 @@ public:
     void add_thread(thread* thrd);
     void remove_thread(thread* thrd);
     void join_all();
-	int size();
+        int size();
 
 private:
     std::list<thread*> m_threads;
diff --git a/src/thread.cpp b/src/thread.cpp
index 8d2f9658..1d4543ff 100644
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -370,7 +370,7 @@ void thread_group::join_all()
 
 int thread_group::size()
 {
-	return m_threads.size();
+        return m_threads.size();
 }
 
 } // namespace boost