diff --git a/README.md b/README.md
index 2a30c69..23f58e2 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,7 @@ Make sure you use the `actions/checkout@v2` action!
     version will be incremented.
   * If a commit message begins with the string "feat" or includes "minor" then the minor version will be increased. This works
     for most common commit metadata for feature additions: `"feat: new API"` and `"feature: new API"`.
+  * If a commit message contains the word "pre-alpha" or "pre-beta" or "pre-rc" then the pre-release version will be increased (for example specifying pre-alpha: 1.6.0-alpha.1 -> 1.6.0-alpha.2 or, specifying pre-beta: 1.6.0-alpha.1 -> 1.6.0-beta.0)
   * All other changes will increment the patch version.
 * Push the bumped npm version in package.json back into the repo.
 * Push a tag for the new version back into the repo.
diff --git a/index.js b/index.js
index e558a44..3053e37 100644
--- a/index.js
+++ b/index.js
@@ -28,12 +28,27 @@ Toolkit.run(async tools => {
 
   const majorWords = process.env['INPUT_MAJOR-WORDING'].split(',')
   const minorWords = process.env['INPUT_MINOR-WORDING'].split(',')
+  const preReleaseWords = ['pre-alpha', 'pre-beta', 'pre-rc']
+
   let version = 'patch'
+  let foundWord = null;
+  
   if (messages.some(
     message => /^([a-zA-Z]+)(\(.+\))?(\!)\:/.test(message) || majorWords.some(word => message.includes(word)))) {
     version = 'major'
   } else if (messages.some(message => minorWords.some(word => message.includes(word)))) {
     version = 'minor'
+  } else if (messages.some(message => preReleaseWords.some(word => {
+        if (message.includes(word)) {
+          foundWord = word;
+          return true;
+        } else {
+          return false;
+        }
+      }
+    ))) {
+      const preid = foundWord.split("-")[1];
+      version = `prerelease --preid=${preid}`;
   }
 
   try {