diff --git a/m-rbtree.h b/m-rbtree.h
index 06972284..5854a54b 100644
--- a/m-rbtree.h
+++ b/m-rbtree.h
@@ -59,6 +59,7 @@
    CLEAR(M_C3(rbtree_, name, _clear)),                                  \
    INIT_MOVE(M_C3(rbtree_, name, _init_move)),                          \
    MOVE(M_C3(rbtree_, name, _move)),                                    \
+   SWAP(M_C3(rbtree_, name, _swap)),                                    \
    TYPE(M_C3(rbtree_,name,_t)),                                         \
    SUBTYPE(M_C3(rbtree_type_,name,_t)),                                 \
    IT_TYPE(M_C3(rbtree_it_,name,_t)),                                   \
@@ -572,6 +573,21 @@ typedef enum {
     RBTREEI_CONTRACT (tree);                                            \
   }                                                                     \
                                                                         \
+  static inline void                                                    \
+  M_C3(rbtree_, name, _swap)(tree_t tree1, tree_t tree2)                \
+  {                                                                     \
+    RBTREEI_CONTRACT (tree1);                                           \
+    RBTREEI_CONTRACT (tree2);                                           \
+    size_t size = tree1->size;                                          \
+    tree1->size = tree2->size;                                          \
+    tree2->size = size;                                                 \
+    node_t *node = tree1->node;                                         \
+    tree1->node = tree2->node;                                          \
+    tree2->node = node;                                                 \
+    RBTREEI_CONTRACT (tree1);                                           \
+    RBTREEI_CONTRACT (tree2);                                           \
+  }                                                                     \
+                                                                        \
   static inline bool                                                    \
   M_C3(rbtree_, name, _empty_p)(const tree_t tree)                      \
   {                                                                     \
diff --git a/tests/test-mrbtree.c b/tests/test-mrbtree.c
index 837ad340..d5db3a7a 100644
--- a/tests/test-mrbtree.c
+++ b/tests/test-mrbtree.c
@@ -94,7 +94,19 @@ static void test_uint(void)
       assert (ptr == NULL);
     }
   }
+
+  rbtree_uint_init (tree);
+  assert(rbtree_uint_empty_p(tree));
+  rbtree_uint_clean(tree2);
+  rbtree_uint_push(tree2, 17421);
+  assert(rbtree_uint_size(tree2) == 1);
+  rbtree_uint_swap(tree, tree2);
+  assert(rbtree_uint_empty_p(tree2));
+  assert(rbtree_uint_size(tree) == 1);
+  unsigned int *ptr = rbtree_uint_get(tree, 17421);
+  assert(ptr != NULL && *ptr == 17421);
   
+  rbtree_uint_clear(tree);
   rbtree_uint_clear(tree2);
 }