diff --git a/examples/angular/infinite-query-with-max-pages/src/app/components/example.component.html b/examples/angular/infinite-query-with-max-pages/src/app/components/example.component.html
index 7afc85afe2..09a8a6c7ef 100644
--- a/examples/angular/infinite-query-with-max-pages/src/app/components/example.component.html
+++ b/examples/angular/infinite-query-with-max-pages/src/app/components/example.component.html
@@ -4,9 +4,11 @@ <h3>4 projects per page</h3>
   <h3>3 pages max</h3>
   @if (query.isPending()) {
     <p>Loading...</p>
-  } @else if (query.isError()) {
+  }
+  @if (query.isError()) {
     <span>Error: {{ query.error().message }}</span>
-  } @else {
+  }
+  @if (query.isSuccess()) {
     <div>
       <button
         (click)="query.fetchPreviousPage()"
diff --git a/packages/angular-query-experimental/src/__tests__/inject-infinite-query.test-d.ts b/packages/angular-query-experimental/src/__tests__/inject-infinite-query.test-d.ts
index 7ec133adfb..588e85af17 100644
--- a/packages/angular-query-experimental/src/__tests__/inject-infinite-query.test-d.ts
+++ b/packages/angular-query-experimental/src/__tests__/inject-infinite-query.test-d.ts
@@ -23,20 +23,121 @@ describe('injectInfiniteQuery', () => {
     vi.useRealTimers()
   })
 
-  test('should narrow type after isSuccess', () => {
-    const query = TestBed.runInInjectionContext(() => {
-      return injectInfiniteQuery(() => ({
-        queryKey: ['infiniteQuery'],
-        queryFn: ({ pageParam }) =>
-          sleep(0).then(() => 'data on page ' + pageParam),
-        initialPageParam: 0,
-        getNextPageParam: () => 12,
-      }))
+  describe('without initialData', () => {
+    test('should narrow type after isSuccess', () => {
+      const query = TestBed.runInInjectionContext(() => {
+        return injectInfiniteQuery(() => ({
+          queryKey: ['infiniteQuery'],
+          queryFn: ({ pageParam }) =>
+            sleep(0).then(() => 'data on page ' + pageParam),
+          initialPageParam: 0,
+          getNextPageParam: () => 12,
+        }))
+      })
+
+      if (query.isSuccess()) {
+        const data = query.data()
+        expectTypeOf(data).toEqualTypeOf<InfiniteData<string, unknown>>()
+      }
+    })
+
+    test('should narrow type after isPending', () => {
+      const query = TestBed.runInInjectionContext(() => {
+        return injectInfiniteQuery(() => ({
+          queryKey: ['infiniteQuery'],
+          queryFn: ({ pageParam }) =>
+            sleep(0).then(() => 'data on page ' + pageParam),
+          initialPageParam: 0,
+          getNextPageParam: () => 12,
+        }))
+      })
+
+      if (query.isPending()) {
+        const data = query.data()
+        expectTypeOf(data).toEqualTypeOf<undefined>()
+      }
+    })
+
+    test('should narrow type after isError', () => {
+      const query = TestBed.runInInjectionContext(() => {
+        return injectInfiniteQuery(() => ({
+          queryKey: ['infiniteQuery'],
+          queryFn: ({ pageParam }) =>
+            sleep(0).then(() => 'data on page ' + pageParam),
+          initialPageParam: 0,
+          getNextPageParam: () => 12,
+        }))
+      })
+
+      if (query.isError()) {
+        const error = query.error()
+        expectTypeOf(error).toEqualTypeOf<Error>()
+      }
+    })
+  })
+
+  describe('with initialData', () => {
+    test('should narrow type after isSuccess', () => {
+      const query = TestBed.runInInjectionContext(() => {
+        return injectInfiniteQuery(() => ({
+          queryKey: ['infiniteQuery'],
+          queryFn: ({ pageParam }) =>
+            sleep(0).then(() => 'data on page ' + pageParam),
+          initialPageParam: 0,
+          getNextPageParam: () => 12,
+          initialData: {
+            pageParams: [0, 1],
+            pages: ['page 0 data', 'page 1 data'],
+          },
+        }))
+      })
+
+      if (query.isSuccess()) {
+        const data = query.data()
+        expectTypeOf(data).toEqualTypeOf<InfiniteData<string, unknown>>()
+      }
+    })
+
+    test('should narrow type after isPending', () => {
+      const query = TestBed.runInInjectionContext(() => {
+        return injectInfiniteQuery(() => ({
+          queryKey: ['infiniteQuery'],
+          queryFn: ({ pageParam }) =>
+            sleep(0).then(() => 'data on page ' + pageParam),
+          initialPageParam: 0,
+          getNextPageParam: () => 12,
+          initialData: {
+            pageParams: [0, 1],
+            pages: ['page 0 data', 'page 1 data'],
+          },
+        }))
+      })
+
+      if (query.isPending()) {
+        const data = query.data()
+        expectTypeOf(data).toEqualTypeOf<InfiniteData<string, unknown>>()
+      }
     })
 
-    if (query.isSuccess()) {
-      const data = query.data()
-      expectTypeOf(data).toEqualTypeOf<InfiniteData<string, unknown>>()
-    }
+    test('should narrow type after isError', () => {
+      const query = TestBed.runInInjectionContext(() => {
+        return injectInfiniteQuery(() => ({
+          queryKey: ['infiniteQuery'],
+          queryFn: ({ pageParam }) =>
+            sleep(0).then(() => 'data on page ' + pageParam),
+          initialPageParam: 0,
+          getNextPageParam: () => 12,
+          initialData: {
+            pageParams: [0, 1],
+            pages: ['page 0 data', 'page 1 data'],
+          },
+        }))
+      })
+
+      if (query.isError()) {
+        const error = query.error()
+        expectTypeOf(error).toEqualTypeOf<Error>()
+      }
+    })
   })
 })
diff --git a/packages/angular-query-experimental/src/__tests__/inject-query.test-d.ts b/packages/angular-query-experimental/src/__tests__/inject-query.test-d.ts
index 541ad65f14..a4aa1858d6 100644
--- a/packages/angular-query-experimental/src/__tests__/inject-query.test-d.ts
+++ b/packages/angular-query-experimental/src/__tests__/inject-query.test-d.ts
@@ -105,6 +105,16 @@ describe('initialData', () => {
         expectTypeOf(query.data).toEqualTypeOf<Signal<{ wow: boolean }>>()
       }
     })
+    it('error should be defined when query is error', () => {
+      const query = injectQuery(() => ({
+        queryKey: ['key'],
+        queryFn: () => ({ wow: true }),
+        initialData: { wow: true },
+      }))
+      if (query.isError()) {
+        expectTypeOf(query.error).toEqualTypeOf<Signal<Error>>()
+      }
+    })
   })
 
   describe('structuralSharing', () => {
diff --git a/packages/angular-query-experimental/src/inject-infinite-query.ts b/packages/angular-query-experimental/src/inject-infinite-query.ts
index ee6de03240..58ac018282 100644
--- a/packages/angular-query-experimental/src/inject-infinite-query.ts
+++ b/packages/angular-query-experimental/src/inject-infinite-query.ts
@@ -121,5 +121,5 @@ export function injectInfiniteQuery(
       injectInfiniteQueryFn,
       InfiniteQueryObserver as typeof QueryObserver,
     ),
-  )
+  ) as unknown as CreateInfiniteQueryResult
 }
diff --git a/packages/angular-query-experimental/src/inject-query.ts b/packages/angular-query-experimental/src/inject-query.ts
index 1dac0ab694..b4138d436a 100644
--- a/packages/angular-query-experimental/src/inject-query.ts
+++ b/packages/angular-query-experimental/src/inject-query.ts
@@ -222,5 +222,5 @@ export function injectQuery(
   !options?.injector && assertInInjectionContext(injectQuery)
   return runInInjectionContext(options?.injector ?? inject(Injector), () =>
     createBaseQuery(injectQueryFn, QueryObserver),
-  ) as unknown as CreateQueryResult
+  ) as unknown as CreateQueryResult | DefinedCreateQueryResult
 }
diff --git a/packages/angular-query-experimental/src/types.ts b/packages/angular-query-experimental/src/types.ts
index 1d4bf86487..f168e0d64f 100644
--- a/packages/angular-query-experimental/src/types.ts
+++ b/packages/angular-query-experimental/src/types.ts
@@ -52,29 +52,45 @@ type CreateStatusBasedQueryResult<
   TStatus extends QueryObserverResult['status'],
   TData = unknown,
   TError = DefaultError,
-> = Extract<QueryObserverResult<TData, TError>, { status: TStatus }>
+  TState = QueryObserverResult<TData, TError>,
+> = Extract<TState, { status: TStatus }>
 
-export interface BaseQueryNarrowing<TData = unknown, TError = DefaultError> {
+type CreateNarrowQueryResult<
+  TData = unknown,
+  TError = DefaultError,
+  TState = QueryObserverResult<TData, TError>,
+  TNarrowState = TState,
+> = BaseQueryNarrowing<TData, TError, TState> &
+  MapToSignals<OmitKeyof<TNarrowState, keyof BaseQueryNarrowing, 'safely'>>
+
+export interface BaseQueryNarrowing<
+  TData = unknown,
+  TError = DefaultError,
+  TState = QueryObserverResult<TData, TError>,
+> {
   isSuccess: (
     this: CreateBaseQueryResult<TData, TError>,
-  ) => this is CreateBaseQueryResult<
+  ) => this is CreateNarrowQueryResult<
     TData,
     TError,
-    CreateStatusBasedQueryResult<'success', TData, TError>
+    TState,
+    CreateStatusBasedQueryResult<'success', TData, TError, TState>
   >
   isError: (
     this: CreateBaseQueryResult<TData, TError>,
-  ) => this is CreateBaseQueryResult<
+  ) => this is CreateNarrowQueryResult<
     TData,
     TError,
-    CreateStatusBasedQueryResult<'error', TData, TError>
+    TState,
+    CreateStatusBasedQueryResult<'error', TData, TError, TState>
   >
   isPending: (
     this: CreateBaseQueryResult<TData, TError>,
-  ) => this is CreateBaseQueryResult<
+  ) => this is CreateNarrowQueryResult<
     TData,
     TError,
-    CreateStatusBasedQueryResult<'pending', TData, TError>
+    TState,
+    CreateStatusBasedQueryResult<'pending', TData, TError, TState>
   >
 }
 
@@ -99,7 +115,7 @@ export type CreateBaseQueryResult<
   TData = unknown,
   TError = DefaultError,
   TState = QueryObserverResult<TData, TError>,
-> = BaseQueryNarrowing<TData, TError> &
+> = BaseQueryNarrowing<TData, TError, TState> &
   MapToSignals<OmitKeyof<TState, keyof BaseQueryNarrowing, 'safely'>>
 
 export type CreateQueryResult<
@@ -111,23 +127,22 @@ export type DefinedCreateQueryResult<
   TData = unknown,
   TError = DefaultError,
   TState = DefinedQueryObserverResult<TData, TError>,
-> = BaseQueryNarrowing<TData, TError> &
+> = BaseQueryNarrowing<TData, TError, TState> &
   MapToSignals<OmitKeyof<TState, keyof BaseQueryNarrowing, 'safely'>>
 
 export type CreateInfiniteQueryResult<
   TData = unknown,
   TError = DefaultError,
-> = BaseQueryNarrowing<TData, TError> &
-  MapToSignals<InfiniteQueryObserverResult<TData, TError>>
+  TState = InfiniteQueryObserverResult<TData, TError>,
+> = BaseQueryNarrowing<TData, TError, TState> &
+  MapToSignals<OmitKeyof<TState, keyof BaseQueryNarrowing, 'safely'>>
 
 export type DefinedCreateInfiniteQueryResult<
   TData = unknown,
   TError = DefaultError,
-  TDefinedInfiniteQueryObserver = DefinedInfiniteQueryObserverResult<
-    TData,
-    TError
-  >,
-> = MapToSignals<TDefinedInfiniteQueryObserver>
+  TState = DefinedInfiniteQueryObserverResult<TData, TError>,
+> = BaseQueryNarrowing<TData, TError, TState> &
+  MapToSignals<OmitKeyof<TState, keyof BaseQueryNarrowing, 'safely'>>
 
 export interface CreateMutationOptions<
   TData = unknown,