diff --git a/packages/react-reconciler/README.md b/packages/react-reconciler/README.md
index 8b0fc1b9eae7d..c2f7991acdb2d 100644
--- a/packages/react-reconciler/README.md
+++ b/packages/react-reconciler/README.md
@@ -187,10 +187,6 @@ You can leave it empty.
 
 This method is called for a container that's used as a portal target. Usually you can leave it empty.
 
-#### `now()`
-
-You can proxy this to `performance.now()` or its equivalent in your environment.
-
 #### `scheduleTimeout(fn, delay)`
 
 You can proxy this to `setTimeout` or its equivalent in your environment.
diff --git a/packages/react-reconciler/src/forks/ReactFiberHostConfig.custom.js b/packages/react-reconciler/src/forks/ReactFiberHostConfig.custom.js
index 8ef999f432fb1..8afc9a3aa2cb9 100644
--- a/packages/react-reconciler/src/forks/ReactFiberHostConfig.custom.js
+++ b/packages/react-reconciler/src/forks/ReactFiberHostConfig.custom.js
@@ -54,7 +54,6 @@ export const createTextInstance = $$$hostConfig.createTextInstance;
 export const scheduleTimeout = $$$hostConfig.scheduleTimeout;
 export const cancelTimeout = $$$hostConfig.cancelTimeout;
 export const noTimeout = $$$hostConfig.noTimeout;
-export const now = $$$hostConfig.now;
 export const isPrimaryRenderer = $$$hostConfig.isPrimaryRenderer;
 export const warnsIfNotActing = $$$hostConfig.warnsIfNotActing;
 export const supportsMutation = $$$hostConfig.supportsMutation;