diff --git a/numpy/core/src/multiarray/refcount.c b/numpy/core/src/multiarray/refcount.c
index eab11e933d03..88f660118339 100644
--- a/numpy/core/src/multiarray/refcount.c
+++ b/numpy/core/src/multiarray/refcount.c
@@ -275,8 +275,12 @@ _fillobject(char *optr, PyObject *obj, PyArray_Descr *dtype)
         }
     }
     else {
-        Py_XINCREF(obj);
-        NPY_COPY_PYOBJECT_PTR(optr, &obj);
+        npy_intp i;
+        for (i = 0; i < dtype->elsize / sizeof(obj); i++) {
+            Py_XINCREF(obj);
+            NPY_COPY_PYOBJECT_PTR(optr, &obj);
+            optr += sizeof(obj);
+        }
         return;
     }
 }
diff --git a/numpy/core/src/multiarray/shape.c b/numpy/core/src/multiarray/shape.c
index d5fde5b9743a..2278b5d5b785 100644
--- a/numpy/core/src/multiarray/shape.c
+++ b/numpy/core/src/multiarray/shape.c
@@ -326,8 +326,12 @@ _putzero(char *optr, PyObject *zero, PyArray_Descr *dtype)
         }
     }
     else {
-        Py_INCREF(zero);
-        NPY_COPY_PYOBJECT_PTR(optr, &zero);
+        npy_intp i;
+        for (i = 0; i < dtype->elsize / sizeof(zero); i++) {
+            Py_INCREF(zero);
+            NPY_COPY_PYOBJECT_PTR(optr, &zero);
+            optr += sizeof(zero);
+        }
     }
     return;
 }
diff --git a/numpy/core/tests/test_multiarray.py b/numpy/core/tests/test_multiarray.py
index 2e40a2b7c3a5..9c51895fa73e 100644
--- a/numpy/core/tests/test_multiarray.py
+++ b/numpy/core/tests/test_multiarray.py
@@ -511,6 +511,10 @@ def test_zeros_obj(self):
         assert_array_equal(d, [0] * 13)
         assert_equal(np.count_nonzero(d), 0)
 
+    def test_zeros_obj_obj(self):
+        d = zeros(10, dtype=[('k', object, 2)])
+        assert_array_equal(d['k'], 0)
+
     def test_sequence_non_homogenous(self):
         assert_equal(np.array([4, 2**80]).dtype, np.object)
         assert_equal(np.array([4, 2**80, 4]).dtype, np.object)
@@ -2784,6 +2788,14 @@ def test_zeros_appended(self):
         assert_array_equal(x[0], np.eye(3))
         assert_array_equal(x[1], np.zeros((3, 3)))
 
+    def test_obj_obj(self):
+        # check memory is initialized on resize, gh-4857
+        a = ones(10, dtype=[('k', object, 2)])
+        a.resize(15,)
+        assert_equal(a.shape, (15,))
+        assert_array_equal(a['k'][-5:], 0)
+        assert_array_equal(a['k'][:-5], 1)
+
 
 class TestRecord(TestCase):
     def test_field_rename(self):