diff --git a/monai/data/utils.py b/monai/data/utils.py
index 988b813272..14217e9103 100644
--- a/monai/data/utils.py
+++ b/monai/data/utils.py
@@ -1473,7 +1473,7 @@ def convert_tables_to_dicts(
     # parse row indices
     rows: list[int | str] = []
     if row_indices is None:
-        rows = slice(df.shape[0])  # type: ignore
+        rows = df.index.tolist()
     else:
         for i in row_indices:
             if isinstance(i, (tuple, list)):
diff --git a/tests/data/test_csv_dataset.py b/tests/data/test_csv_dataset.py
index 71be4fdd22..56bac5cead 100644
--- a/tests/data/test_csv_dataset.py
+++ b/tests/data/test_csv_dataset.py
@@ -179,6 +179,20 @@ def prepare_csv_file(data, filepath):
                 },
             )
 
+            # test pre-loaded DataFrame subset
+            df = pd.read_csv(filepath1)
+            df_subset = df.iloc[[1, 3, 4]]
+            dataset = CSVDataset(src=df_subset, col_groups={"ehr": [f"ehr_{i}" for i in range(3)]})
+            self.assertEqual(len(dataset), 3)
+            np.testing.assert_allclose([round(i, 4) for i in dataset[1]["ehr"]], [3.3333, 3.2353, 3.4000])
+
+            # test pre-loaded DataFrame subset with row_indices != None
+            df = pd.read_csv(filepath1)
+            df_subset = df.iloc[[1, 3, 4]]
+            dataset = CSVDataset(src=df_subset, row_indices=[1, 3], col_groups={"ehr": [f"ehr_{i}" for i in range(3)]})
+            self.assertEqual(len(dataset), 2)
+            np.testing.assert_allclose([round(i, 4) for i in dataset[1]["ehr"]], [3.3333, 3.2353, 3.4000])
+
             # test pre-loaded multiple DataFrames, join tables with kwargs
             dfs = [pd.read_csv(i) for i in filepaths]
             dataset = CSVDataset(src=dfs, on="subject_id")