diff --git a/lemon/core.h b/lemon/core.h
--- a/lemon/core.h
+++ b/lemon/core.h
@@ -24,6 +24,7 @@
 
 #include <lemon/bits/enable_if.h>
 #include <lemon/bits/traits.h>
+#include <lemon/assert.h>
 
 ///\file
 ///\brief LEMON core utilities.
diff --git a/lemon/dfs.h b/lemon/dfs.h
--- a/lemon/dfs.h
+++ b/lemon/dfs.h
@@ -27,7 +27,6 @@
 #include <lemon/bits/path_dump.h>
 #include <lemon/core.h>
 #include <lemon/error.h>
-#include <lemon/assert.h>
 #include <lemon/maps.h>
 #include <lemon/path.h>
 
diff --git a/lemon/lgf_reader.h b/lemon/lgf_reader.h
--- a/lemon/lgf_reader.h
+++ b/lemon/lgf_reader.h
@@ -31,7 +31,6 @@
 #include <set>
 #include <map>
 
-#include <lemon/assert.h>
 #include <lemon/core.h>
 
 #include <lemon/lgf_writer.h>
diff --git a/lemon/lgf_writer.h b/lemon/lgf_writer.h
--- a/lemon/lgf_writer.h
+++ b/lemon/lgf_writer.h
@@ -33,7 +33,6 @@
 #include <vector>
 #include <functional>
 
-#include <lemon/assert.h>
 #include <lemon/core.h>
 #include <lemon/maps.h>