diff --git a/README.markdown b/README.markdown
index 7257027..70ccbaf 100644
--- a/README.markdown
+++ b/README.markdown
@@ -28,6 +28,8 @@ To use it, add it to your `project.clj`:
                  :rules cljx.rules/cljs-rules}]}
 ```
 
+Can be run "once" or "auto", in which case it will watch all source-paths for changes to .cljx files.  Defaults to "once".
+
 Add
 
 ```clojure
diff --git a/project.clj b/project.clj
index 7f1ed18..064b48b 100644
--- a/project.clj
+++ b/project.clj
@@ -1,4 +1,4 @@
-(defproject com.keminglabs/cljx "0.1.3"
+(defproject com.keminglabs/cljx "0.1.4"
 
   :description "Static Clojure code rewriting"
   :url "http://github.com/lynaghk/cljx"
@@ -6,6 +6,7 @@
             :url "http://www.opensource.org/licenses/BSD-3-Clause"}
 
   :dependencies [[org.clojure/core.logic "0.7.0"]
-                 [jonase/kibit "0.0.3"]]
+                 [jonase/kibit "0.0.3"]
+                 [watchtower "0.1.1"]]
 
   :eval-in-leiningen true)
diff --git a/src/leiningen/cljx.clj b/src/leiningen/cljx.clj
index ce1d17c..7065a47 100644
--- a/src/leiningen/cljx.clj
+++ b/src/leiningen/cljx.clj
@@ -1,5 +1,6 @@
 (ns leiningen.cljx
-  (:use [cljx.core :only [generate]]))
+  (:use [cljx.core :only [generate]]
+        [watchtower.core :only [watcher* watch rate file-filter on-change extensions]]))
 
 
 (def no-opts-warning "You need a :cljx entry in your project.clj! It should look something like:\n
@@ -8,18 +9,41 @@
          :cljs-output-path \".generated/cljs\"}
 ")
 
+(defn- cljx-compile [builds]
+  "The actual static transform, separated out so it can be called repeatedly."
+  (doseq [{:keys [source-paths output-path extension rules include-meta]
+           :or {extension "clj" include-meta false}} builds]
+    (let [rules (eval rules)]
+      (doseq [p source-paths]
+        (binding [*print-meta* include-meta]
+          (generate p output-path extension rules))))))
+
+(defn- once
+  "Transform .cljx files once and then exit."
+  [builds]
+  (cljx-compile builds))
+
+(defn- auto
+  "Watch .cljx files and transform them after any changes."
+  [builds]
+  (let [dirs (set (flatten (map :source-paths builds)))]
+    (println "Watching" (vec dirs) "for changes.")
+    (-> (watcher* dirs)
+        (file-filter (extensions :cljx))
+        (rate 1000)
+        (on-change (fn [_] (cljx-compile builds)))
+        (watch))))
+
 (defn cljx
   "Statically transform .cljx files into Clojure and ClojureScript sources."
-  [project]
-
-  (if-let [opts (:cljx project)]
-    (if-let [{builds :builds} opts]
-      (doseq [{:keys [source-paths output-path extension rules include-meta]
-               :or {extension "clj" include-meta false}} builds]
+  {:subtasks [#'once #'auto]}
+  ([project] (cljx project "once"))
+  ([project subtask]
 
-        (let [rules (eval rules)]
-          (doseq [p source-paths]
-            (binding [*print-meta* include-meta]
-              (generate p output-path extension rules))))))
+      (if-let [opts (:cljx project)]
+        (if-let [{builds :builds} opts]
+          (case subtask
+            "once" (once builds)
+            "auto" (auto builds)))
 
-    (println no-opts-warning)))
+        (println no-opts-warning))))