diff --git a/conformance/tests/basic/inferencepool_invalid_epp_service.go b/conformance/tests/basic/inferencepool_invalid_epp_service.go
new file mode 100644
index 000000000..cfbeb2840
--- /dev/null
+++ b/conformance/tests/basic/inferencepool_invalid_epp_service.go
@@ -0,0 +1,79 @@
+/*
+Copyright 2025 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package basic
+
+import (
+	"net/http"
+	"testing"
+
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/types"
+	"sigs.k8s.io/gateway-api/conformance/utils/kubernetes"
+	"sigs.k8s.io/gateway-api/conformance/utils/suite"
+	"sigs.k8s.io/gateway-api/pkg/features"
+
+	"sigs.k8s.io/gateway-api-inference-extension/conformance/tests"
+	gatewayv1 "sigs.k8s.io/gateway-api/apis/v1"
+	conformancehttp "sigs.k8s.io/gateway-api/conformance/utils/http"
+)
+
+func init() {
+	tests.ConformanceTests = append(tests.ConformanceTests, InferencePoolInvalidEPPService)
+}
+
+var InferencePoolInvalidEPPService = suite.ConformanceTest{
+	ShortName:   "InferencePoolInvalidEPPService",
+	Description: "An HTTPRoute that references an InferencePool with a non-existent EPP service should have a ResolvedRefs condition with a status of False and a reason of BackendNotFound.",
+	Manifests:   []string{"tests/basic/inferencepool_invalid_epp_service.yaml"},
+	Features: []features.FeatureName{
+		features.SupportGateway,
+		features.SupportHTTPRoute,
+		features.FeatureName("SupportInferencePool"),
+	},
+	Test: func(t *testing.T, s *suite.ConformanceTestSuite) {
+		const (
+			routePath      = "/invalid-epp-test"
+			infraNamespace = "gateway-conformance-infra"
+			appNamespace   = "gateway-conformance-app-backend"
+		)
+
+		routeNN := types.NamespacedName{Name: "httproute-for-invalid-epp-pool", Namespace: appNamespace}
+		gwNN := types.NamespacedName{Name: "conformance-gateway", Namespace: infraNamespace}
+
+		gwAddr := kubernetes.GatewayAndHTTPRoutesMustBeAccepted(t, s.Client, s.TimeoutConfig, s.ControllerName, kubernetes.NewGatewayRef(gwNN), routeNN)
+
+		t.Run("HTTPRoute has a ResolvedRefs Condition with status False and Reason BackendNotFound", func(t *testing.T) {
+			resolvedRefsCond := metav1.Condition{
+				Type:   string(gatewayv1.RouteConditionResolvedRefs),
+				Status: metav1.ConditionFalse,
+				Reason: string(gatewayv1.RouteReasonBackendNotFound),
+			}
+			kubernetes.HTTPRouteMustHaveCondition(t, s.Client, s.TimeoutConfig, routeNN, gwNN, resolvedRefsCond)
+		})
+
+		t.Run("Request to a route with an invalid backend reference receives a 500 response", func(t *testing.T) {
+			conformancehttp.MakeRequestAndExpectEventuallyConsistentResponse(t, s.RoundTripper, s.TimeoutConfig, gwAddr, conformancehttp.ExpectedResponse{
+				Request: conformancehttp.Request{
+					Path: routePath,
+				},
+				Response: conformancehttp.Response{
+					StatusCode: http.StatusInternalServerError,
+				},
+			})
+		})
+	},
+}
diff --git a/conformance/tests/basic/inferencepool_invalid_epp_service.yaml b/conformance/tests/basic/inferencepool_invalid_epp_service.yaml
new file mode 100644
index 000000000..00941bb32
--- /dev/null
+++ b/conformance/tests/basic/inferencepool_invalid_epp_service.yaml
@@ -0,0 +1,31 @@
+apiVersion: inference.networking.x-k8s.io/v1alpha2
+kind: InferencePool
+metadata:
+  name: pool-with-invalid-epp
+  namespace: gateway-conformance-app-backend
+spec:
+  selector:
+    app: "inference-model-1"
+  targetPortNumber: 3000
+  extensionRef:
+    name: non-existent-epp-svc
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: HTTPRoute
+metadata:
+  name: httproute-for-invalid-epp-pool
+  namespace: gateway-conformance-app-backend
+spec:
+  parentRefs:
+  - name: conformance-gateway
+    namespace: gateway-conformance-infra
+  rules:
+  - backendRefs:
+    - name: pool-with-invalid-epp
+      kind: InferencePool
+      group: inference.networking.x-k8s.io
+      port: 80
+    matches:
+    - path:
+        type: PathPrefix
+        value: /invalid-epp-test