diff --git a/miplearn/features/sample.py b/miplearn/features/sample.py
index 078c847..5f6f85f 100644
--- a/miplearn/features/sample.py
+++ b/miplearn/features/sample.py
@@ -19,6 +19,7 @@ Vector = Union[
     List[int],
     List[float],
     List[Optional[str]],
+    np.ndarray,
 ]
 VectorList = Union[
     List[List[bool]],
@@ -86,12 +87,16 @@ class Sample(ABC):
         assert False, f"Scalar expected; found instead: {value}"
 
     def _assert_is_vector(self, value: Any) -> None:
-        assert isinstance(value, list), f"List expected; found instead: {value}"
+        assert isinstance(
+            value, (list, np.ndarray)
+        ), f"List or numpy array expected; found instead: {value}"
         for v in value:
             self._assert_is_scalar(v)
 
     def _assert_is_vector_list(self, value: Any) -> None:
-        assert isinstance(value, list), f"List expected; found instead: {value}"
+        assert isinstance(
+            value, (list, np.ndarray)
+        ), f"List or numpy array expected; found instead: {value}"
         for v in value:
             if v is None:
                 continue
diff --git a/tests/features/test_sample.py b/tests/features/test_sample.py
index e07355f..3051470 100644
--- a/tests/features/test_sample.py
+++ b/tests/features/test_sample.py
@@ -3,8 +3,10 @@
 #  Released under the modified BSD license. See COPYING.md for more details.
 from tempfile import NamedTemporaryFile
 from typing import Any
+import numpy as np
 
 from miplearn.features.sample import MemorySample, Sample, Hdf5Sample, _pad, _crop
+from miplearn.solvers.tests import assert_equals
 
 
 def test_memory_sample() -> None:
@@ -28,6 +30,7 @@ def _test_sample(sample: Sample) -> None:
     _assert_roundtrip_vector(sample, [True, True, False])
     _assert_roundtrip_vector(sample, [1, 2, 3])
     _assert_roundtrip_vector(sample, [1.0, 2.0, 3.0])
+    _assert_roundtrip_vector(sample, np.array([1.0, 2.0, 3.0]), check_type=False)
 
     # VectorList
     _assert_roundtrip_vector_list(sample, [["A"], ["BB", "CCC"], None])
@@ -66,12 +69,15 @@ def _assert_roundtrip_scalar(sample: Sample, expected: Any) -> None:
     _assert_same_type(actual, expected)
 
 
-def _assert_roundtrip_vector(sample: Sample, expected: Any) -> None:
+def _assert_roundtrip_vector(
+    sample: Sample, expected: Any, check_type: bool = True
+) -> None:
     sample.put_vector("key", expected)
     actual = sample.get_vector("key")
-    assert actual == expected
+    assert_equals(actual, expected)
     assert actual is not None
-    _assert_same_type(actual[0], expected[0])
+    if check_type:
+        _assert_same_type(actual[0], expected[0])
 
 
 def _assert_roundtrip_vector_list(sample: Sample, expected: Any) -> None: