diff --git a/src/transformers/loss/loss_d_fine.py b/src/transformers/loss/loss_d_fine.py
index 383d29ef404b..351a7a72b185 100644
--- a/src/transformers/loss/loss_d_fine.py
+++ b/src/transformers/loss/loss_d_fine.py
@@ -337,37 +337,43 @@ def DFineForObjectDetectionLoss(
     auxiliary_outputs = None
     if config.auxiliary_loss:
         if denoising_meta_values is not None:
-            dn_out_coord, outputs_coord = torch.split(
+            dn_out_coord, normal_out_coord = torch.split(
                 outputs_coord.clamp(min=0, max=1), denoising_meta_values["dn_num_split"], dim=2
             )
-            dn_out_class, outputs_class = torch.split(outputs_class, denoising_meta_values["dn_num_split"], dim=2)
+            dn_out_class, normal_out_class = torch.split(outputs_class, denoising_meta_values["dn_num_split"], dim=2)
             dn_out_corners, out_corners = torch.split(predicted_corners, denoising_meta_values["dn_num_split"], dim=2)
             dn_out_refs, out_refs = torch.split(initial_reference_points, denoising_meta_values["dn_num_split"], dim=2)
+        else:
+            normal_out_coord = outputs_coord.clamp(min=0, max=1)
+            normal_out_class = outputs_class
+            out_corners = predicted_corners
+            out_refs = initial_reference_points
 
+        if config.auxiliary_loss:
             auxiliary_outputs = _set_aux_loss2(
-                outputs_class[:, :-1].transpose(0, 1),
-                outputs_coord[:, :-1].transpose(0, 1),
+                normal_out_class[:, :-1].transpose(0, 1),
+                normal_out_coord[:, :-1].transpose(0, 1),
                 out_corners[:, :-1].transpose(0, 1),
                 out_refs[:, :-1].transpose(0, 1),
                 out_corners[:, -1],
-                outputs_class[:, -1],
+                normal_out_class[:, -1],
             )
-
             outputs_loss["auxiliary_outputs"] = auxiliary_outputs
             outputs_loss["auxiliary_outputs"].extend(
                 _set_aux_loss([enc_topk_logits], [enc_topk_bboxes.clamp(min=0, max=1)])
             )
 
-            dn_auxiliary_outputs = _set_aux_loss2(
-                dn_out_class.transpose(0, 1),
-                dn_out_coord.transpose(0, 1),
-                dn_out_corners.transpose(0, 1),
-                dn_out_refs.transpose(0, 1),
-                dn_out_corners[:, -1],
-                dn_out_class[:, -1],
-            )
-            outputs_loss["dn_auxiliary_outputs"] = dn_auxiliary_outputs
-            outputs_loss["denoising_meta_values"] = denoising_meta_values
+            if denoising_meta_values is not None:
+                dn_auxiliary_outputs = _set_aux_loss2(
+                    dn_out_class.transpose(0, 1),
+                    dn_out_coord.transpose(0, 1),
+                    dn_out_corners.transpose(0, 1),
+                    dn_out_refs.transpose(0, 1),
+                    dn_out_corners[:, -1],
+                    dn_out_class[:, -1],
+                )
+                outputs_loss["dn_auxiliary_outputs"] = dn_auxiliary_outputs
+                outputs_loss["denoising_meta_values"] = denoising_meta_values
 
     loss_dict = criterion(outputs_loss, labels)
 
diff --git a/tests/models/d_fine/test_modeling_d_fine.py b/tests/models/d_fine/test_modeling_d_fine.py
index c3101ff997f7..d70394812f36 100644
--- a/tests/models/d_fine/test_modeling_d_fine.py
+++ b/tests/models/d_fine/test_modeling_d_fine.py
@@ -615,6 +615,49 @@ def _validate_backbone_init(config):
         config = config.__class__(**config_dict)
         _validate_backbone_init(config)
 
+    def test_auxiliary_losses_without_denoising(self):
+        """Auxiliary losses should still be computed when num_denoising=0. Regression test for #45593."""
+        config = copy.deepcopy(self.model_tester.get_config())
+        config.num_denoising = 0
+        config.auxiliary_loss = True
+        config.num_labels = self.model_tester.num_labels
+
+        model = DFineForObjectDetection(config)
+        model.to(torch_device)
+        model.train()
+
+        pixel_values = torch.rand(
+            self.model_tester.batch_size,
+            self.model_tester.num_channels,
+            self.model_tester.image_size,
+            self.model_tester.image_size,
+        ).to(torch_device)
+        labels = []
+        for _ in range(self.model_tester.batch_size):
+            labels.append(
+                {
+                    "class_labels": torch.randint(0, self.model_tester.num_labels, (self.model_tester.n_targets,)).to(
+                        torch_device
+                    ),
+                    "boxes": torch.rand(self.model_tester.n_targets, 4).to(torch_device),
+                }
+            )
+
+        outputs = model(pixel_values=pixel_values, labels=labels)
+
+        # Main loss must exist
+        self.assertIsNotNone(outputs.loss)
+
+        # Aux losses MUST exist when denoising is off
+        self.assertTrue(
+            any("aux" in k for k in outputs.loss_dict), "Auxiliary losses should be computed even when num_denoising=0"
+        )
+
+        # Denoising losses must NOT exist when denoising is off
+        self.assertFalse(
+            any("dn_" in k for k in outputs.loss_dict), "Denoising losses should not be present when num_denoising=0"
+        )
+
     @parameterized.expand(["float32", "float16", "bfloat16"])
     @require_torch_accelerator
     @slow