diff --git a/tests/core/test_rnn.py b/tests/core/test_rnn.py
new file mode 100644
index 000000000..a1bd52905
--- /dev/null
+++ b/tests/core/test_rnn.py
@@ -0,0 +1,275 @@
+import unittest
+
+import torch
+
+from pyhealth.datasets import create_sample_dataset, get_dataloader
+from pyhealth.models import RNN
+from pyhealth.models.rnn import MultimodalRNN
+
+
+class TestRNN(unittest.TestCase):
+    """Test cases for the RNN model."""
+
+    def setUp(self):
+        """Set up test data and model."""
+        self.samples = [
+            {
+                "patient_id": "patient-0",
+                "visit_id": "visit-0",
+                "conditions": ["cond-33", "cond-86", "cond-80", "cond-12"],
+                "procedures": ["proc-12", "proc-45", "proc-23"],
+                "label": 0,
+            },
+            {
+                "patient_id": "patient-1",
+                "visit_id": "visit-1",
+                "conditions": ["cond-33", "cond-86", "cond-80"],
+                "procedures": ["proc-12"],
+                "label": 1,
+            },
+        ]
+
+        self.input_schema = {
+            "conditions": "sequence",
+            "procedures": "sequence",
+        }
+        self.output_schema = {"label": "binary"}
+
+        self.dataset = create_sample_dataset(
+            samples=self.samples,
+            input_schema=self.input_schema,
+            output_schema=self.output_schema,
+            dataset_name="test",
+        )
+
+        self.model = RNN(dataset=self.dataset)
+
+    def test_model_initialization(self):
+        """Test that the RNN model initializes correctly."""
+        self.assertIsInstance(self.model, RNN)
+        self.assertEqual(self.model.embedding_dim, 128)
+        self.assertEqual(self.model.hidden_dim, 128)
+        self.assertEqual(len(self.model.feature_keys), 2)
+        self.assertIn("conditions", self.model.feature_keys)
+        self.assertIn("procedures", self.model.feature_keys)
+        self.assertEqual(self.model.label_key, "label")
+
+    def test_model_forward(self):
+        """Test that the RNN model forward pass works correctly."""
+        train_loader = get_dataloader(self.dataset, batch_size=2, shuffle=True)
+        data_batch = next(iter(train_loader))
+
+        with torch.no_grad():
+            ret = self.model(**data_batch)
+
+        self.assertIn("loss", ret)
+        self.assertIn("y_prob", ret)
+        self.assertIn("y_true", ret)
+        self.assertIn("logit", ret)
+
+        self.assertEqual(ret["y_prob"].shape[0], 2)
+        self.assertEqual(ret["y_true"].shape[0], 2)
+        self.assertEqual(ret["logit"].shape[0], 2)
+        self.assertEqual(ret["loss"].dim(), 0)
+
+    def test_model_backward(self):
+        """Test that the RNN model backward pass works correctly."""
+        train_loader = get_dataloader(self.dataset, batch_size=2, shuffle=True)
+        data_batch = next(iter(train_loader))
+
+        ret = self.model(**data_batch)
+        ret["loss"].backward()
+
+        has_gradient = False
+        for param in self.model.parameters():
+            if param.requires_grad and param.grad is not None:
+                has_gradient = True
+                break
+        self.assertTrue(
+            has_gradient, "No parameters have gradients after backward pass"
+        )
+
+    def test_model_with_embedding(self):
+        """Test that the RNN model returns embeddings when requested."""
+        train_loader = get_dataloader(self.dataset, batch_size=2, shuffle=True)
+        data_batch = next(iter(train_loader))
+        data_batch["embed"] = True
+
+        with torch.no_grad():
+            ret = self.model(**data_batch)
+
+        self.assertIn("embed", ret)
+        self.assertEqual(ret["embed"].shape[0], 2)
+        expected_embed_dim = len(self.model.feature_keys) * self.model.hidden_dim
+        self.assertEqual(ret["embed"].shape[1], expected_embed_dim)
+
+    def test_custom_hyperparameters(self):
+        """Test RNN model with custom hyperparameters."""
+        model = RNN(
+            dataset=self.dataset,
+            embedding_dim=64,
+            hidden_dim=32,
+        )
+
+        self.assertEqual(model.embedding_dim, 64)
+        self.assertEqual(model.hidden_dim, 32)
+
+        train_loader = get_dataloader(self.dataset, batch_size=2, shuffle=True)
+        data_batch = next(iter(train_loader))
+
+        with torch.no_grad():
+            ret = model(**data_batch)
+
+        self.assertIn("loss", ret)
+        self.assertIn("y_prob", ret)
+
+    def test_rnn_type_lstm(self):
+        """Test RNN model with LSTM cell type."""
+        model = RNN(
+            dataset=self.dataset,
+            rnn_type="LSTM",
+        )
+
+        train_loader = get_dataloader(self.dataset, batch_size=2, shuffle=True)
+        data_batch = next(iter(train_loader))
+
+        with torch.no_grad():
+            ret = model(**data_batch)
+
+        self.assertIn("loss", ret)
+        self.assertEqual(ret["y_prob"].shape[0], 2)
+
+    def test_rnn_type_vanilla(self):
+        """Test RNN model with vanilla RNN cell type."""
+        model = RNN(
+            dataset=self.dataset,
+            rnn_type="RNN",
+        )
+
+        train_loader = get_dataloader(self.dataset, batch_size=2, shuffle=True)
+        data_batch = next(iter(train_loader))
+
+        with torch.no_grad():
+            ret = model(**data_batch)
+
+        self.assertIn("loss", ret)
+        self.assertEqual(ret["y_prob"].shape[0], 2)
+
+    def test_bidirectional(self):
+        """Test RNN model with bidirectional layers."""
+        model = RNN(
+            dataset=self.dataset,
+            bidirectional=True,
+        )
+
+        train_loader = get_dataloader(self.dataset, batch_size=2, shuffle=True)
+        data_batch = next(iter(train_loader))
+
+        with torch.no_grad():
+            ret = model(**data_batch)
+
+        self.assertIn("loss", ret)
+        self.assertEqual(ret["y_prob"].shape[0], 2)
+
+
+class TestMultimodalRNN(unittest.TestCase):
+    """Test cases for the MultimodalRNN model with mixed input modalities."""
+
+    def setUp(self):
+        """Set up test data with both sequential and non-sequential features."""
+        self.samples = [
+            {
+                "patient_id": "patient-0",
+                "visit_id": "visit-0",
+                "conditions": ["cond-33", "cond-86", "cond-80"],
+                "demographics": ["asian", "male"],
+                "vitals": [120.0, 80.0, 98.6],
+                "label": 1,
+            },
+            {
+                "patient_id": "patient-1",
+                "visit_id": "visit-1",
+                "conditions": ["cond-12", "cond-52"],
+                "demographics": ["white", "female"],
+                "vitals": [110.0, 75.0, 98.2],
+                "label": 0,
+            },
+        ]
+
+        self.input_schema = {
+            "conditions": "sequence",
+            "demographics": "multi_hot",
+            "vitals": "tensor",
+        }
+        self.output_schema = {"label": "binary"}
+
+        self.dataset = create_sample_dataset(
+            samples=self.samples,
+            input_schema=self.input_schema,
+            output_schema=self.output_schema,
+            dataset_name="test",
+        )
+
+        self.model = MultimodalRNN(dataset=self.dataset)
+
+    def test_model_initialization(self):
+        """Test that the MultimodalRNN model initializes correctly."""
+        self.assertIsInstance(self.model, MultimodalRNN)
+        self.assertEqual(len(self.model.feature_keys), 3)
+        self.assertIn("conditions", self.model.sequential_features)
+        self.assertIn("demographics", self.model.non_sequential_features)
+        self.assertIn("vitals", self.model.non_sequential_features)
+
+    def test_model_forward(self):
+        """Test that the MultimodalRNN forward pass works correctly."""
+        train_loader = get_dataloader(self.dataset, batch_size=2, shuffle=True)
+        data_batch = next(iter(train_loader))
+
+        with torch.no_grad():
+            ret = self.model(**data_batch)
+
+        self.assertIn("loss", ret)
+        self.assertIn("y_prob", ret)
+        self.assertIn("y_true", ret)
+        self.assertIn("logit", ret)
+
+        self.assertEqual(ret["y_prob"].shape[0], 2)
+        self.assertEqual(ret["loss"].dim(), 0)
+
+    def test_model_backward(self):
+        """Test that the MultimodalRNN backward pass works correctly."""
+        train_loader = get_dataloader(self.dataset, batch_size=2, shuffle=True)
+        data_batch = next(iter(train_loader))
+
+        ret = self.model(**data_batch)
+        ret["loss"].backward()
+
+        has_gradient = False
+        for param in self.model.parameters():
+            if param.requires_grad and param.grad is not None:
+                has_gradient = True
+                break
+        self.assertTrue(
+            has_gradient, "No parameters have gradients after backward pass"
+        )
+
+    def test_model_with_embedding(self):
+        """Test that the MultimodalRNN returns embeddings when requested."""
+        train_loader = get_dataloader(self.dataset, batch_size=2, shuffle=True)
+        data_batch = next(iter(train_loader))
+        data_batch["embed"] = True
+
+        with torch.no_grad():
+            ret = self.model(**data_batch)
+
+        self.assertIn("embed", ret)
+        self.assertEqual(ret["embed"].shape[0], 2)
+        expected_embed_dim = (
+            len(self.model.sequential_features) * self.model.hidden_dim
+            + len(self.model.non_sequential_features) * self.model.embedding_dim
+        )
+        self.assertEqual(ret["embed"].shape[1], expected_embed_dim)
+
+
+if __name__ == "__main__":
+    unittest.main()