diff --git a/Runtime/safe-ds/safeds/data/tabular/_column.py b/Runtime/safe-ds/safeds/data/tabular/_column.py
index c19433ed7..3d9c7ac85 100644
--- a/Runtime/safe-ds/safeds/data/tabular/_column.py
+++ b/Runtime/safe-ds/safeds/data/tabular/_column.py
@@ -331,10 +331,10 @@ def mode(self) -> Any:
 
         Returns
         -------
-        mode :
-            The mode value.
+        List :
+            Returns a list with the most common values.
         """
-        return self._column._data.mode()[0]
+        return self._column._data.mode().tolist()
 
     def median(self) -> float:
         """
@@ -443,7 +443,7 @@ def stability(self) -> float:
         if self._column._data.size == 0:
             raise ColumnSizeError("> 0", "0")
         return (
-            self._column._data.value_counts()[self._column.statistics.mode()]
+            self._column._data.value_counts()[self._column.statistics.mode()[0]]
             / self._column._data.count()
         )
 
diff --git a/Runtime/safe-ds/safeds/data/tabular/transformation/_imputer.py b/Runtime/safe-ds/safeds/data/tabular/transformation/_imputer.py
index 2e4e8d8ea..2fcb76570 100644
--- a/Runtime/safe-ds/safeds/data/tabular/transformation/_imputer.py
+++ b/Runtime/safe-ds/safeds/data/tabular/transformation/_imputer.py
@@ -4,7 +4,7 @@
 from typing import Any, Optional
 
 import pandas as pd
-from safeds.data.tabular import Table
+from safeds.data.tabular import ColumnStatistics, Table
 from sklearn.impute import SimpleImputer
 
 
@@ -86,6 +86,13 @@ def fit(self, table: Table, column_names: Optional[list[str]] = None) -> None:
         if column_names is None:
             column_names = table.schema.get_column_names()
 
+        if self._imp.strategy == "most_frequent":
+            for name in column_names:
+                if 1 < len(ColumnStatistics(table.get_column(name)).mode()):
+                    raise IndexError(
+                        "There are multiple frequent values in a column given for the Imputer"
+                    )
+
         self._column_names = column_names
         indices = [
             table.schema._get_column_index_by_name(name) for name in self._column_names
diff --git a/Runtime/safe-ds/tests/data/tabular/_column/test_mode.py b/Runtime/safe-ds/tests/data/tabular/_column/test_mode.py
index fd6fc1bd2..721af5073 100644
--- a/Runtime/safe-ds/tests/data/tabular/_column/test_mode.py
+++ b/Runtime/safe-ds/tests/data/tabular/_column/test_mode.py
@@ -5,10 +5,16 @@
 def test_mode_valid() -> None:
     table = Table(pd.DataFrame(data={"col1": [1, 2, 3, 4, 3]}))
     column = table.get_column("col1")
-    assert column.statistics.mode() == 3
+    assert column.statistics.mode() == [3]
 
 
 def test_mode_valid_str() -> None:
     table = Table(pd.DataFrame(data={"col1": ["1", "2", "3", "4", "3"]}))
     column = table.get_column("col1")
-    assert column.statistics.mode() == "3"
+    assert column.statistics.mode() == ["3"]
+
+
+def test_mode_valid_list() -> None:
+    table = Table(pd.DataFrame(data={"col1": ["1", "4", "3", "4", "3"]}))
+    column = table.get_column("col1")
+    assert column.statistics.mode() == ["3", "4"]
diff --git a/Runtime/safe-ds/tests/data/tabular/_table/test_summary.py b/Runtime/safe-ds/tests/data/tabular/_table/test_summary.py
index 823a47c14..b7b4e8cd2 100644
--- a/Runtime/safe-ds/tests/data/tabular/_table/test_summary.py
+++ b/Runtime/safe-ds/tests/data/tabular/_table/test_summary.py
@@ -25,7 +25,7 @@ def test_summary() -> None:
                     "2",
                     "1",
                     str(4.0 / 3),
-                    "1",
+                    "[1]",
                     "1.0",
                     "4",
                     str(1.0 / 3),
@@ -38,7 +38,7 @@ def test_summary() -> None:
                     "-",
                     "-",
                     "-",
-                    "a",
+                    "['a', 'b', 'c']",
                     "-",
                     "-",
                     "-",
@@ -50,5 +50,4 @@ def test_summary() -> None:
             }
         )
     )
-
     assert truth == table.summary()
diff --git a/Runtime/safe-ds/tests/data/tabular/transformation/_imputer/test_imputer.py b/Runtime/safe-ds/tests/data/tabular/transformation/_imputer/test_imputer.py
index ba56e9338..6fe2e0723 100644
--- a/Runtime/safe-ds/tests/data/tabular/transformation/_imputer/test_imputer.py
+++ b/Runtime/safe-ds/tests/data/tabular/transformation/_imputer/test_imputer.py
@@ -1,5 +1,6 @@
 import numpy as np
 import pandas as pd
+import pytest
 from safeds.data.tabular import Table
 from safeds.data.tabular.transformation import Imputer
 
@@ -23,12 +24,19 @@ def test_imputer_median() -> None:
 
 
 def test_imputer_mode() -> None:
-    table = Table(pd.DataFrame(data={"col1": [np.nan, 2, 3, 4, 5]}))
+    table = Table(pd.DataFrame(data={"col1": [np.nan, 2, 2, 4, 5]}))
     column = table.get_column("col1")
     imp = Imputer(Imputer.Strategy.Mode())
     new_table = imp.fit_transform(table)
 
-    assert new_table.get_column("col1")._data[0] == column.statistics.mode()
+    assert new_table.get_column("col1")._data[0] == column.statistics.mode()[0]
+
+
+def test_imputer_mode_invalid() -> None:
+    table = Table(pd.DataFrame(data={"col1": [np.nan, 2, 3, 4, 5]}))
+    imp = Imputer(Imputer.Strategy.Mode())
+    with pytest.raises(IndexError):
+        imp.fit_transform(table)
 
 
 def test_imputer_constant() -> None: