diff --git a/Handler/Package.hs b/Handler/Package.hs
index 940dd77..fc99d99 100644
--- a/Handler/Package.hs
+++ b/Handler/Package.hs
@@ -10,6 +10,7 @@ import qualified Data.Text.Encoding as T
 import           Data.Time (addUTCTime)
 import           Database.Esqueleto ((^.), (&&.), Value (Value))
 import qualified Database.Esqueleto as E
+import qualified Database.Persist as P
 import           Formatting
 import           Import
 import           Text.Email.Validate
@@ -22,7 +23,8 @@ getPackageR pn = do
         asInt = id
         haddocksLink ident version =
             HaddockR ident [concat [toPathPiece pn, "-", toPathPiece version]]
-    (packages, downloads, recentDownloads, Entity _ metadata) <- runDB $ do
+    muid <- maybeAuthId
+    (packages, downloads, recentDownloads, nLikes, liked, Entity _ metadata) <- runDB $ do
         packages <- fmap (map reformat) $ E.select $ E.from $ \(p, s) -> do
             E.where_ $ (p ^. PackageStackage E.==. s ^. StackageId)
                    &&. (p ^. PackageName' E.==. E.val pn)
@@ -31,12 +33,19 @@ getPackageR pn = do
             E.limit maxSnaps
             --selectList [PackageName' ==. pn] [LimitTo 10, Desc PackageStackage]
             return (p ^. PackageVersion, s ^. StackageTitle, s ^. StackageIdent, s ^. StackageHasHaddocks)
+        nLikes <- count [LikePackage ==. pn]
+        let getLiked uid = (>0) <$> count [LikePackage ==. pn, LikeVoter ==. uid]
+        liked <- maybe (return False) getLiked muid
         downloads <- count [DownloadPackage ==. pn]
         now <- liftIO getCurrentTime
         let nowMinus30 = addUTCTime (-30 * 24 * 60 * 60) now
         recentDownloads <- count [DownloadPackage ==. pn, DownloadTimestamp >=. nowMinus30]
         metadata <- getBy404 (UniqueMetadata pn)
-        return (packages, downloads, recentDownloads, metadata)
+
+        return (packages, downloads, recentDownloads, nLikes, liked, metadata)
+
+    let likedClass = if liked then "fa-thumbs-up" else "fa-thumbs-o-up" :: Text
+
     let deps = enumerate (metadataDeps metadata)
         authors = enumerate (parseIdentitiesLiberally (metadataAuthor metadata))
         maintainers = let ms = enumerate (parseIdentitiesLiberally (metadataMaintainer metadata))
@@ -151,3 +160,19 @@ renderEmail = T.decodeUtf8 . toByteString
 -- | Format a number with commas nicely.
 formatNum :: Int -> Text
 formatNum = sformat commas
+
+postPackageLikeR :: PackageName -> Handler ()
+postPackageLikeR packageName = maybeAuthId >>= \muid -> case muid of
+    Nothing -> return ()
+    Just uid -> do
+      runDB $ P.insert $ Like packageName uid
+      return ()
+
+postPackageUnlikeR :: PackageName -> Handler ()
+postPackageUnlikeR name = maybeAuthId >>= \muid -> case muid of
+    Nothing -> return ()
+    Just uid -> do
+      runDB $ E.delete $ E.from $ \like ->
+        E.where_ $ like ^. LikePackage E.==. E.val name
+               &&. like ^. LikeVoter E.==. E.val uid
+      return ()
diff --git a/config/models b/config/models
index 3e17533..593ff09 100644
--- a/config/models
+++ b/config/models
@@ -47,6 +47,10 @@ Tag
     tag Slug
     voter UserId
 
+Like
+    package PackageName
+    voter UserId
+
 Download
     ident PackageSetIdent Maybe
     view HackageView Maybe
diff --git a/config/routes b/config/routes
index 015dfd8..199cc1d 100644
--- a/config/routes
+++ b/config/routes
@@ -27,3 +27,5 @@
 /package/#PackageName PackageR GET
 /package PackageListR GET
 /compressor-status CompressorStatusR GET
+/package/#PackageName/like PackageLikeR POST
+/package/#PackageName/unlike PackageUnlikeR POST
diff --git a/templates/package.hamlet b/templates/package.hamlet
index c77417d..0cf469f 100644
--- a/templates/package.hamlet
+++ b/templates/package.hamlet
@@ -32,9 +32,11 @@ $newline never
                         <button .btn>Add
             <div .social>
                 <span #likes>
-                    #{formatNum 234}
+                    #{nLikes}
                 \ likes #
-                <i class="fa fa-thumbs-o-up" onclick="this.className = 'fa fa-thumbs-up'; document.getElementById('likes').innerText = '235'"></i>
+                $if isJust muid
+                  <i .fa.#{likedClass}
+                    onclick="toggleLike(this)"></i>
                 $if downloads /= 0
                     <span .downloads>
                         $if downloads /= recentDownloads
diff --git a/templates/package.julius b/templates/package.julius
index fe28c2a..197e24a 100644
--- a/templates/package.julius
+++ b/templates/package.julius
@@ -9,3 +9,25 @@ $(function(){
     }
   });
 });
+
+function toggleLike(el) {
+    var $this = $(el);
+    var action = 'like';
+    if ($this.hasClass('fa-thumbs-up')) {
+        action = 'unlike';
+    }
+
+    $this.toggleClass('fa-thumbs-up');
+    $this.toggleClass('fa-thumbs-o-up');
+
+    $likes = $('#likes');
+    nLikes = parseInt($likes.text(), 10);
+
+    if (action == 'like') {
+        $likes.text(nLikes + 1);
+        $.post("@{PackageLikeR pn}");
+    } else {
+        $likes.text(nLikes - 1);
+        $.post("@{PackageUnlikeR pn}");
+    }
+}
diff --git a/templates/package.lucius b/templates/package.lucius
index 84c9fca..5e26a5d 100644
--- a/templates/package.lucius
+++ b/templates/package.lucius
@@ -49,6 +49,9 @@ h3 {
   .fa-thumbs-o-up:hover {
     color: #3f4549
   }
+  .fa-thumbs-up {
+    cursor: pointer;
+  }
 }
 .dependencies {
   margin-top: 0.5em;