diff --git a/package.json b/package.json
index 1622c33..f74bffa 100644
--- a/package.json
+++ b/package.json
@@ -83,6 +83,7 @@
     "@types/react-dom": "^19.0.0",
     "@vitejs/plugin-react": "^4.3.3",
     "@vitest/browser-playwright": "^4.0.0-beta.15",
+    "@vitest/utils": "^4.0.17",
     "bumpp": "^9.4.2",
     "changelogithub": "^0.13.9",
     "eslint": "^9.8.0",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index c4d7d9c..d3448cb 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -23,6 +23,9 @@ importers:
       '@vitest/browser-playwright':
         specifier: ^4.0.0-beta.15
         version: 4.0.0-beta.15(playwright@1.55.1)(vite@7.1.9(jiti@2.6.1)(tsx@4.17.0)(yaml@2.5.0))(vitest@4.0.0-beta.15)
+      '@vitest/utils':
+        specifier: ^4.0.17
+        version: 4.0.17
       bumpp:
         specifier: ^9.4.2
         version: 9.4.2
@@ -1690,6 +1693,9 @@ packages:
   '@vitest/pretty-format@4.0.0-beta.15':
     resolution: {integrity: sha512-DZS8SxaBxuIWLlJH7AwaH8oKbQZnxydN1iYksJThgk9A4ap7xol9YR1QwKS01psYUbXueOB3073BwxqueRwLyA==}
 
+  '@vitest/pretty-format@4.0.17':
+    resolution: {integrity: sha512-Ah3VAYmjcEdHg6+MwFE17qyLqBHZ+ni2ScKCiW2XrlSBV4H3Z7vYfPfz7CWQ33gyu76oc0Ai36+kgLU3rfF4nw==}
+
   '@vitest/runner@4.0.0-beta.15':
     resolution: {integrity: sha512-SJUTRfTNJkhkvY51HPk5wBw46TJr4IScj+TQhAAWLDHSL1nctzN1qFe8xbmMyZvJW18SfqMh8DPdcdiRLMVMYA==}
 
@@ -1702,6 +1708,9 @@ packages:
   '@vitest/utils@4.0.0-beta.15':
     resolution: {integrity: sha512-MRs6D//FeZp1kQGyF4fyPZ4YVmlV/topjmiT0iYGBVZYafXAwpXChQhzdW0EIsfjMDsOMWckChKtubvAb6ZnHA==}
 
+  '@vitest/utils@4.0.17':
+    resolution: {integrity: sha512-RG6iy+IzQpa9SB8HAFHJ9Y+pTzI+h8553MrciN9eC6TFBErqrQaTas4vG+MVj8S4uKk8uTT2p0vgZPnTdxd96w==}
+
   '@vue/compiler-core@3.4.35':
     resolution: {integrity: sha512-gKp0zGoLnMYtw4uS/SJRRO7rsVggLjvot3mcctlMXunYNsX+aRJDqqw/lV5/gHK91nvaAAlWFgdVl020AW1Prg==}
 
@@ -5532,6 +5541,10 @@ snapshots:
     dependencies:
       tinyrainbow: 3.0.3
 
+  '@vitest/pretty-format@4.0.17':
+    dependencies:
+      tinyrainbow: 3.0.3
+
   '@vitest/runner@4.0.0-beta.15':
     dependencies:
       '@vitest/utils': 4.0.0-beta.15
@@ -5550,6 +5563,11 @@ snapshots:
       '@vitest/pretty-format': 4.0.0-beta.15
       tinyrainbow: 3.0.3
 
+  '@vitest/utils@4.0.17':
+    dependencies:
+      '@vitest/pretty-format': 4.0.17
+      tinyrainbow: 3.0.3
+
   '@vue/compiler-core@3.4.35':
     dependencies:
       '@babel/parser': 7.28.4
diff --git a/src/pure.tsx b/src/pure.tsx
index 79fb5d1..d90a97e 100644
--- a/src/pure.tsx
+++ b/src/pure.tsx
@@ -1,11 +1,22 @@
 import type { Locator, LocatorSelectors, PrettyDOMOptions } from 'vitest/browser'
-import { page, utils } from 'vitest/browser'
+import { page, server, utils } from 'vitest/browser'
 import React from 'react'
 import type { Container } from 'react-dom/client'
 import ReactDOMClient from 'react-dom/client'
+import { nanoid } from '@vitest/utils/helpers'
 
 const { debug, getElementLocatorSelectors } = utils
 
+function getTestIdAttribute() {
+  return server.config.browser.locators.testIdAttribute
+}
+
+function ensureTestIdAttribute(element: HTMLElement) {
+  if (!element.hasAttribute(getTestIdAttribute())) {
+    element.setAttribute(getTestIdAttribute(), nanoid())
+  }
+}
+
 let activeActs = 0
 
 function setActEnvironment(env: boolean | undefined): void {
@@ -80,6 +91,11 @@ export async function render(
     container = baseElement.appendChild(document.createElement('div'))
   }
 
+  // Ensuring testid attributes exists so that the generated locators will be stable
+  // https://github.com/vitest-community/vitest-browser-react/issues/42
+  ensureTestIdAttribute(baseElement)
+  ensureTestIdAttribute(container)
+
   let root: ReactRoot
 
   if (!mountedContainers.has(container)) {
diff --git a/test/__snapshots__/render.test.tsx.snap b/test/__snapshots__/render.test.tsx.snap
index 2a39517..01c7759 100644
--- a/test/__snapshots__/render.test.tsx.snap
+++ b/test/__snapshots__/render.test.tsx.snap
@@ -1,7 +1,9 @@
 // Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
 
 exports[`renders simple component 1`] = `
-<div>
+<div
+  data-testid="stable-snapshot"
+>
   <div>
     Hello World
   </div>
diff --git a/test/render-selector.test.tsx b/test/render-selector.test.tsx
new file mode 100644
index 0000000..0ace10c
--- /dev/null
+++ b/test/render-selector.test.tsx
@@ -0,0 +1,25 @@
+import { expect, test } from 'vitest'
+import { render } from 'vitest-browser-react'
+import { page, server } from 'vitest/browser'
+
+test('should apply and use a unique testid as the root selector when it does not exists', async () => {
+  const screen = await render(<div>Render</div>)
+  const selector = page.elementLocator(screen.baseElement).selector
+
+  expect(selector).toMatch(/^internal:testid=\[[^\]]*\]$/)
+})
+
+test('should apply and use a unique testid as the locator selector when using default container', async () => {
+  const screen = await render(<div>Render</div>)
+
+  expect(screen.locator.selector).toMatch(/^internal:testid=\[[^\]]*\]$/)
+})
+
+test('should not override testid attribute if already set', async () => {
+  document.body.setAttribute(server.config.browser.locators.testIdAttribute, 'custom-id')
+
+  const screen = await render(<div>Render</div>)
+  const selector = page.elementLocator(screen.baseElement).selector
+
+  expect(selector).toBe(`internal:testid=[${server.config.browser.locators.testIdAttribute}="custom-id"s]`)
+})
diff --git a/test/render.test.tsx b/test/render.test.tsx
index 5592f91..06c9ace 100644
--- a/test/render.test.tsx
+++ b/test/render.test.tsx
@@ -1,5 +1,5 @@
 import { expect, test, vi } from 'vitest'
-import { page, userEvent } from 'vitest/browser'
+import { page, server, userEvent } from 'vitest/browser'
 import { Button } from 'react-aria-components'
 import { Suspense } from 'react'
 import { render } from 'vitest-browser-react'
@@ -10,6 +10,8 @@ import { SuspendedHelloWorld } from './fixtures/SuspendedHelloWorld'
 test('renders simple component', async () => {
   const screen = await render(<HelloWorld />)
   await expect.element(page.getByText('Hello World')).toBeVisible()
+
+  screen.container.setAttribute(server.config.browser.locators.testIdAttribute, 'stable-snapshot')
   expect(screen.container).toMatchSnapshot()
 })
 
diff --git a/vitest.config.ts b/vitest.config.ts
index 38abbed..71e54a9 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -16,6 +16,10 @@ export default defineConfig({
         test: { name: 'dev' },
         resolve: { conditions: ['vdev'] },
       },
+      {
+        extends: true,
+        test: { name: 'selector-custom-attr', include: ['test/render-selector.test.tsx'], browser: { locators: { testIdAttribute: 'data-custom-test-id' } } },
+      },
     ],
     printConsoleTrace: true,
     browser: {