diff --git a/brainiak/searchlight/searchlight.py b/brainiak/searchlight/searchlight.py
index c829311e9..1b05f507e 100644
--- a/brainiak/searchlight/searchlight.py
+++ b/brainiak/searchlight/searchlight.py
@@ -420,18 +420,37 @@ def run_block_function(self, block_fn, extra_block_fn_params=None,
             processes = usable_cpus
         else:
             processes = min(pool_size, usable_cpus)
-        with Pool(processes) as pool:
+
+        if processes > 1:
+            with Pool(processes) as pool:
+                for idx, block in enumerate(self.blocks):
+                    result = pool.apply_async(
+                        block_fn,
+                        ([subproblem[idx] for subproblem in self.subproblems],
+                         self.submasks[idx],
+                         self.sl_rad,
+                         self.bcast_var,
+                         extra_block_fn_params))
+                    results.append((block[0], result))
+                local_outputs = [(result[0], result[1].get())
+                                 for result in results]
+        else:
+            # If we only are using one CPU core, no need to create a Pool,
+            # cause an underlying fork(), and send the data to that process.
+            # Just do it here in serial. This  will save copying the memory
+            # and will stop a fork() which can cause problems in some MPI
+            # implementations.
             for idx, block in enumerate(self.blocks):
-                result = pool.apply_async(
-                    block_fn,
-                    ([subproblem[idx] for subproblem in self.subproblems],
-                     self.submasks[idx],
-                     self.sl_rad,
-                     self.bcast_var,
-                     extra_block_fn_params))
+                subprob_list = [subproblem[idx]
+                                for subproblem in self.subproblems]
+                result = block_fn(
+                            subprob_list,
+                            self.submasks[idx],
+                            self.sl_rad,
+                            self.bcast_var,
+                            extra_block_fn_params)
                 results.append((block[0], result))
-            local_outputs = [(result[0], result[1].get())
-                             for result in results]
+            local_outputs = [(result[0], result[1]) for result in results]
 
         # Collect results
         global_outputs = self.comm.gather(local_outputs)
diff --git a/tests/searchlight/test_searchlight.py b/tests/searchlight/test_searchlight.py
index f6da405fc..7d472e6f5 100644
--- a/tests/searchlight/test_searchlight.py
+++ b/tests/searchlight/test_searchlight.py
@@ -60,6 +60,36 @@ def test_searchlight_with_cube():
                     assert global_outputs[i, j, k] is None
 
 
+def test_searchlight_with_cube_poolsize_1():
+    sl = Searchlight(sl_rad=3)
+    comm = MPI.COMM_WORLD
+    rank = comm.rank
+    size = comm.size
+    dim0, dim1, dim2 = (50, 50, 50)
+    ntr = 30
+    nsubj = 3
+    mask = np.zeros((dim0, dim1, dim2), dtype=np.bool)
+    data = [np.empty((dim0, dim1, dim2, ntr), dtype=np.object)
+            if i % size == rank
+            else None
+            for i in range(0, nsubj)]
+
+    # Put a spot in the mask
+    mask[10:17, 10:17, 10:17] = True
+
+    sl.distribute(data, mask)
+    global_outputs = sl.run_searchlight(cube_sfn, pool_size=1)
+
+    if rank == 0:
+        assert global_outputs[13, 13, 13] == 1.0
+        global_outputs[13, 13, 13] = None
+
+        for i in range(global_outputs.shape[0]):
+            for j in range(global_outputs.shape[1]):
+                for k in range(global_outputs.shape[2]):
+                    assert global_outputs[i, j, k] is None
+
+
 def diamond_sfn(l, msk, myrad, bcast_var):
     assert not np.any(msk[~Diamond(3).mask_])
     if np.all(msk[Diamond(3).mask_]):