diff --git a/bigframes/core/indexes/base.py b/bigframes/core/indexes/base.py
index 41b32d99e4..998f7c754c 100644
--- a/bigframes/core/indexes/base.py
+++ b/bigframes/core/indexes/base.py
@@ -533,6 +533,16 @@ def value_counts(
 
         return series.Series(block)
 
+    def isna(self) -> Index:
+        return self._apply_unary_op(ops.isnull_op)
+
+    isnull = isna
+
+    def notna(self) -> Index:
+        return self._apply_unary_op(ops.notnull_op)
+
+    notnull = notna
+
     def fillna(self, value=None) -> Index:
         if self.nlevels > 1:
             raise TypeError("Multiindex does not support 'fillna'")
diff --git a/tests/system/small/test_index.py b/tests/system/small/test_index.py
index 0ec1fb6143..849589f4ab 100644
--- a/tests/system/small/test_index.py
+++ b/tests/system/small/test_index.py
@@ -300,6 +300,20 @@ def test_index_fillna(scalars_df_index, scalars_pandas_df_index):
     pd.testing.assert_index_equal(bf_result, pd_result)
 
 
+def test_index_isna(scalars_df_index, scalars_pandas_df_index):
+    bf_result = scalars_df_index.set_index("int64_col").index.isna().to_pandas()
+    pd_result = scalars_pandas_df_index.set_index("int64_col").index.isna()
+
+    pd.testing.assert_index_equal(bf_result, pd.Index(pd_result))
+
+
+def test_index_notna(scalars_df_index, scalars_pandas_df_index):
+    bf_result = scalars_df_index.set_index("float64_col").index.notna().to_pandas()
+    pd_result = scalars_pandas_df_index.set_index("float64_col").index.notna()
+
+    pd.testing.assert_index_equal(bf_result, pd.Index(pd_result))
+
+
 def test_index_drop(scalars_df_index, scalars_pandas_df_index):
     bf_result = (
         scalars_df_index.set_index("int64_col").index.drop([2, 314159]).to_pandas()
diff --git a/third_party/bigframes_vendored/pandas/core/indexes/base.py b/third_party/bigframes_vendored/pandas/core/indexes/base.py
index d21056a8cf..f01dcca52b 100644
--- a/third_party/bigframes_vendored/pandas/core/indexes/base.py
+++ b/third_party/bigframes_vendored/pandas/core/indexes/base.py
@@ -962,6 +962,38 @@ def fillna(self, value) -> Index:
         """
         raise NotImplementedError(constants.ABSTRACT_METHOD_ERROR_MESSAGE)
 
+    def isna(self):
+        """
+        Detect missing values.
+
+        Return a boolean same-sized object indicating if the values are NA.
+        NA values, such as ``None``, :attr:`numpy.NaN` or :attr:`pd.NaT`, get
+        mapped to ``True`` values.
+        Everything else get mapped to ``False`` values. Characters such as
+        empty strings `''` or :attr:`numpy.inf` are not considered NA values.
+
+        Returns:
+            Index:
+                Boolean index to indicate which entries are NA.
+        """
+        raise NotImplementedError(constants.ABSTRACT_METHOD_ERROR_MESSAGE)
+
+    def notna(self):
+        """
+        Detect existing (non-missing) values.
+
+        Return a boolean same-sized object indicating if the values are not NA.
+        Non-missing values get mapped to ``True``. Characters such as empty
+        strings ``''`` or :attr:`numpy.inf` are not considered NA values.
+        NA values, such as None or :attr:`numpy.NaN`, get mapped to ``False``
+        values.
+
+        Returns:
+            Index:
+                Boolean index to indicate which entries are not NA.
+        """
+        raise NotImplementedError(constants.ABSTRACT_METHOD_ERROR_MESSAGE)
+
     def rename(self, name, *, inplace):
         """
         Alter Index or MultiIndex name.