diff --git a/pandas/tests/frame/test_reductions.py b/pandas/tests/frame/test_reductions.py
index 4d8f163197416..ddce4be070e7b 100644
--- a/pandas/tests/frame/test_reductions.py
+++ b/pandas/tests/frame/test_reductions.py
@@ -1043,6 +1043,30 @@ def test_sum_bools(self):
         bools = isna(df)
         assert bools.sum(axis=1)[0] == 10
 
+    @pytest.mark.parametrize(
+        "df, expected",
+        [
+            (
+                DataFrame({"a": ["483", "3"], "b": ["94", "759"]}),
+                Series(["48394", "3759"]),
+            ),
+            (
+                DataFrame({"a": ["483.948", "3.0"], "b": ["94.2", "759.93"]}),
+                Series(["483.94894.2", "3.0759.93"]),
+            ),
+            (
+                DataFrame({"a": ["483", "3.0"], "b": ["94.2", "79"]}),
+                Series(["48394.2", "3.079"]),
+            ),
+        ],
+    )
+    def test_sum_string_dtype_coercion(self, df, expected):
+        # GH#22642
+        # Check that summing numeric strings results in concatenation
+        # and not conversion to dtype int64 or float64
+        result = df.sum(axis=1)
+        tm.assert_series_equal(result, expected)
+
     # ----------------------------------------------------------------------
     # Index of max / min