diff --git a/numpy/random/mtrand/mtrand.pyx b/numpy/random/mtrand/mtrand.pyx
index 3f6af86b1c00..8f79780d3b83 100644
--- a/numpy/random/mtrand/mtrand.pyx
+++ b/numpy/random/mtrand/mtrand.pyx
@@ -691,10 +691,13 @@ cdef class RandomState:
         """
         cdef ndarray state "arrayObject_state"
         state = <ndarray>np.empty(624, np.uint)
-        memcpy(<void*>PyArray_DATA(state), <void*>(self.internal_state.key), 624*sizeof(long))
+        with self.lock:
+            memcpy(<void*>PyArray_DATA(state), <void*>(self.internal_state.key), 624*sizeof(long))
+            has_gauss = self.internal_state.has_gauss
+            gauss = self.internal_state.gauss
+            pos = self.internal_state.pos
         state = <ndarray>np.asarray(state, np.uint32)
-        return ('MT19937', state, self.internal_state.pos,
-            self.internal_state.has_gauss, self.internal_state.gauss)
+        return ('MT19937', state, pos, has_gauss, gauss)
 
     def set_state(self, state):
         """
@@ -761,10 +764,11 @@ cdef class RandomState:
             obj = <ndarray>PyArray_ContiguousFromObject(key, NPY_LONG, 1, 1)
         if PyArray_DIM(obj, 0) != 624:
             raise ValueError("state must be 624 longs")
-        memcpy(<void*>(self.internal_state.key), <void*>PyArray_DATA(obj), 624*sizeof(long))
-        self.internal_state.pos = pos
-        self.internal_state.has_gauss = has_gauss
-        self.internal_state.gauss = cached_gaussian
+        with self.lock:
+            memcpy(<void*>(self.internal_state.key), <void*>PyArray_DATA(obj), 624*sizeof(long))
+            self.internal_state.pos = pos
+            self.internal_state.has_gauss = has_gauss
+            self.internal_state.gauss = cached_gaussian
 
     # Pickling support:
     def __getstate__(self):