diff --git a/src/mrpro/operators/functionals/SSIM.py b/src/mrpro/operators/functionals/SSIM.py
index 9947bde60..1300c6ccf 100644
--- a/src/mrpro/operators/functionals/SSIM.py
+++ b/src/mrpro/operators/functionals/SSIM.py
@@ -246,8 +246,8 @@ def forward(self, x: torch.Tensor) -> tuple[torch.Tensor]:
             See this PyTorch `discussion <https://discuss.pytorch.org/t/is-model-forward-x-the-same-as-model-call-x/33460/3>`_.
         """
         ssim = ssim3d(
-            self.target.real,
-            x.real,
+            self.target,
+            x,
             weight=self.weight,
             k1=self.k1,
             k2=self.k2,
diff --git a/tests/operators/functionals/test_ssim.py b/tests/operators/functionals/test_ssim.py
index e701c2197..4b156af27 100644
--- a/tests/operators/functionals/test_ssim.py
+++ b/tests/operators/functionals/test_ssim.py
@@ -46,3 +46,16 @@ def test_ssim_reduction() -> None:
     assert ssim_volume.shape == (2, 3)
     assert ssim_full.shape == ()
     assert ssim_none.shape == (2, 3, 4, 4, 4)
+
+
+def test_ssim_complex() -> None:
+    """Test the SSIM functional for complex-valued tensors."""
+    rng = RandomGenerator(0)
+    target_real = rng.float32_tensor((1, 10, 10), low=0.0, high=1.0)
+    target_imag = rng.float32_tensor((1, 10, 10), low=0.0, high=1.0)
+    target = target_real + 1j * target_imag
+    test = rng.complex64_tensor((1, 10, 10), low=0.0, high=1.0)
+
+    torch.testing.assert_close(
+        SSIM(target)(test)[0], 0.5 * (SSIM(target.real)(test.real)[0] + (SSIM(target.imag)(test.imag)[0]))
+    )