diff --git a/include/sparsemap.h b/include/sparsemap.h
index 67b9364..bf749aa 100644
--- a/include/sparsemap.h
+++ b/include/sparsemap.h
@@ -264,7 +264,7 @@ void sparsemap_scan(sparsemap_t *map, void (*scanner)(sm_idx_t vec[], size_t n),
  * \b other bitmap while removing them from \b map.
  *
  * @param[in] map The sparsemap reference.
-* @param[in] other The bitmap to merge into \b map.
+ * @param[in] other The bitmap to merge into \b map.
  */
 void sparsemap_merge(sparsemap_t *map, sparsemap_t *other);
 
diff --git a/src/sparsemap.c b/src/sparsemap.c
index 58d42c5..726a047 100644
--- a/src/sparsemap.c
+++ b/src/sparsemap.c
@@ -109,6 +109,7 @@ enum __SM_CHUNK_INFO {
 };
 
 #define SM_CHUNK_GET_FLAGS(from, at) (((from)) & ((sm_bitvec_t)SM_FLAG_MASK << ((at)*2))) >> ((at)*2)
+#define SM_NEXT_CHUNK_ADDR(chunk)  (uint8_t *)((chunk) + sizeof(sm_idx_t) + __sm_chunk_map_get_size((__sm_chunk_t *)&(chunk)));
 
 typedef struct {
   sm_bitvec_t *m_data;
@@ -763,7 +764,6 @@ __sm_get_chunk_map_data(sparsemap_t *map, size_t offset)
  *
  * @param[in] map The sparsemap_t in question.
  * @returns a pointer after the end of the used data
- * @todo could this simply use m_data_used?
  */
 static uint8_t *
 __sm_get_chunk_map_end(sparsemap_t *map)
@@ -1247,30 +1247,57 @@ sparsemap_scan(sparsemap_t *map, void (*scanner)(sm_idx_t[], size_t), size_t ski
   }
 }
 
+void
+__sm_chunk_map_merge(sparsemap_t *map, sparsemap_idx_t offset, __sm_chunk_t src) {
+  size_t capacity = __sm_chunk_map_get_capacity(&src);
+  for (sparsemap_idx_t j = 0; j < capacity; j++, offset++) {
+    if (__sm_chunk_map_is_set(&src, j)) {
+      sparsemap_set(map, offset, true);
+    }
+  }
+}
+
 void
 sparsemap_merge(sparsemap_t *map, sparsemap_t *other)
 {
-  uint8_t *next_dst, *dst = __sm_get_chunk_map_data(map, 0);
-
-  /* |src| points to the |other| (source) chunk map */
-  uint8_t *next_src, *src = __sm_get_chunk_map_data(other, 0);
+  uint8_t *dst = __sm_get_chunk_map_data(map, 0),
+          *dst_tail = __sm_get_chunk_map_end(map),
+          *src = __sm_get_chunk_map_data(other, 0);
 
   size_t i, src_count = __sm_get_chunk_map_count(other), dst_count = __sm_get_chunk_map_count(map);
-  for (i = 0; i < dst_count; i++) {
+  for (i = 0; i < src_count + dst_count;) {
+    __sm_chunk_t src_chunk, dst_chunk;
     sm_idx_t src_start = *(sm_idx_t *)src;
     sm_idx_t dst_start = *(sm_idx_t *)dst;
-    __sm_chunk_t src_chunk, dst_chunk;
     __sm_chunk_map_init(&src_chunk, src + sizeof(sm_idx_t));
     __sm_chunk_map_init(&dst_chunk, dst + sizeof(sm_idx_t));
+
     if (src_start == dst_start) {
-      __sm_chunk_map_merge(dst, src);
-    } else {
-      next_dst = dst + sizeof(sm_idx_t) + __sm_chunk_map_get_size(&dst_chunk);
-      next_src = dst + sizeof(sm_idx_t) + __sm_chunk_map_get_size(&src_chunk);
-      if (src_start != next_dst) {
-        // Copy the chunk.
-      } else {
-        
+      /* Chunks overlap, merge them. */
+      __sm_chunk_map_merge(map, src_start, src_chunk);
+      src = SM_NEXT_CHUNK_ADDR(src);
+      dst = SM_NEXT_CHUNK_ADDR(dst);
+      i += 2;
+    } else if (src_start < dst_start || i > dst_count) {
+      /* Copy the src chunk into the dest map. */
+      size_t s = __sm_chunk_map_get_size(&src_chunk);
+
+      /* Copy the index (sm_idx_t) */
+      *(sm_idx_t *)dst_tail = src_start;
+      dst_tail += sizeof(sm_idx_t);
+
+      /* Copy the chunk data to the buffer. */
+      memcpy(dst_tail, src, s);
+
+      /* Update the chunk count and data_used. */
+      map->m_data_used = 0;
+      __sm_set_chunk_map_count(map, __sm_get_chunk_map_count(map) + 1);
+
+      src = SM_NEXT_CHUNK_ADDR(src);
+      i += 1;
+      if (i > dst_count) {
+        dst = SM_NEXT_CHUNK_ADDR(dst);
+        i += 1;
       }
     }
   }
@@ -1363,7 +1390,7 @@ sparsemap_split(sparsemap_t *map, sparsemap_idx_t offset, sparsemap_t *other)
     __sm_chunk_map_set_capacity(&s_chunk, offset % capacity);
   }
 
-  /* Now continue with all remaining minimaps. */
+  /* Now continue with all remaining chunk maps. */
   for (; i < count; i++) {
     sm_idx_t start = *(sm_idx_t *)src;
     src += sizeof(sm_idx_t);
diff --git a/tests/test.c b/tests/test.c
index 1e930d9..ac226da 100644
--- a/tests/test.c
+++ b/tests/test.c
@@ -605,6 +605,56 @@ test_api_split(const MunitParameter params[], void *data)
   return MUNIT_OK;
 }
 
+static void *
+test_api_merge_setup(const MunitParameter params[], void *user_data)
+{
+  (void)params;
+  (void)user_data;
+  sparsemap_t *map = sparsemap(10 * 1024);
+  assert_ptr_not_null(map);
+  return (void *)map;
+}
+static void
+test_api_merge_tear_down(void *fixture)
+{
+  sparsemap_t *map = (sparsemap_t *)fixture;
+  assert_ptr_not_null(map);
+  munit_free(map);
+}
+static MunitResult
+test_api_merge(const MunitParameter params[], void *data)
+{
+  sparsemap_t *map = (sparsemap_t *)data;
+  sparsemap_t *other = sparsemap(1024);
+  (void)params;
+
+  assert_ptr_not_null(map);
+  assert_ptr_not_null(other);
+
+  sparsemap_set(map, 0, true);
+  sparsemap_set(other, 1, true);
+  sparsemap_set(other, 2049, true);
+  sparsemap_set(other, 8193, true);
+  sparsemap_set(other, 8194, true);
+  sparsemap_merge(map,other);
+
+  assert_true(sparsemap_is_set(map, 0));
+  assert_true(sparsemap_is_set(map, 1));
+  assert_true(sparsemap_is_set(map, 2049));
+  assert_true(sparsemap_is_set(map, 8193));
+  assert_true(sparsemap_is_set(map, 8194));
+
+  for (int i = 0; i < 10000; i++) {
+    if (i == 0 || i == 1 || i == 2049 || i == 8193 || i == 8194)
+      continue;
+    else
+      assert_false(sparsemap_is_set(map, i));
+  }
+
+  free(other);
+  return MUNIT_OK;
+}
+
 static void *
 test_api_select_setup(const MunitParameter params[], void *user_data)
 {
@@ -919,6 +969,7 @@ static MunitTest api_test_suite[] = {
   { (char *)"/get_size", test_api_get_size, test_api_get_size_setup, test_api_get_size_tear_down, MUNIT_TEST_OPTION_NONE, NULL },
   { (char *)"/scan", test_api_scan, test_api_scan_setup, test_api_scan_tear_down, MUNIT_TEST_OPTION_NONE, NULL },
   { (char *)"/split", test_api_split, test_api_split_setup, test_api_split_tear_down, MUNIT_TEST_OPTION_NONE, NULL },
+  { (char *)"/merge", test_api_merge, test_api_merge_setup, test_api_merge_tear_down, MUNIT_TEST_OPTION_NONE, NULL },
   { (char *)"/select/true", test_api_select, test_api_select_setup, test_api_select_tear_down, MUNIT_TEST_OPTION_NONE, NULL },
 #ifdef SELECT_FALSE
   { (char *)"/select/false", test_api_select_false, test_api_select_false_setup, test_api_select_false_tear_down, MUNIT_TEST_OPTION_NONE, NULL },