diff --git a/src/main/scala/app/PullRequestsController.scala b/src/main/scala/app/PullRequestsController.scala
index dee821f..6fb1656 100644
--- a/src/main/scala/app/PullRequestsController.scala
+++ b/src/main/scala/app/PullRequestsController.scala
@@ -6,35 +6,62 @@
 import org.eclipse.jgit.treewalk.CanonicalTreeParser
 import util.JGitUtil.{DiffInfo, CommitInfo}
 import scala.collection.mutable.ArrayBuffer
+import org.eclipse.jgit.api.Git
+import org.eclipse.jgit.lib.ObjectId
 
 class PullRequestsController extends PullRequestsControllerBase
   with RepositoryService with AccountService with ReferrerAuthenticator
 
 trait PullRequestsControllerBase extends ControllerBase {
-  self: ReferrerAuthenticator =>
+  self: ReferrerAuthenticator with RepositoryService =>
 
   get("/:owner/:repository/pulls")(referrersOnly { repository =>
     pulls.html.list(repository)
   })
 
   // TODO Replace correct authenticator
+  get("/:owner/:repository/pulls/compare")(referrersOnly { newRepo =>
+    (newRepo.repository.originUserName, newRepo.repository.originRepositoryName) match {
+      case (None,_)|(_, None) => NotFound // TODO BadRequest?
+      case (Some(originUserName), Some(originRepositoryName)) => {
+        getRepository(originUserName, originRepositoryName, baseUrl).map { oldRepo =>
+          withGit(
+            getRepositoryDir(originUserName, originRepositoryName),
+            getRepositoryDir(params("owner"), params("repository"))
+          ){ (oldGit, newGit) =>
+            val oldBranch = JGitUtil.getDefaultBranch(oldGit, oldRepo).get._2
+            val newBranch = JGitUtil.getDefaultBranch(newGit, newRepo).get._2
+
+            redirect(s"${context.path}/${newRepo.owner}/${newRepo.name}/pulls/compare/${originUserName}:${oldBranch}...${newBranch}")
+          }
+        } getOrElse NotFound
+      }
+    }
+  })
+
+  // TODO Replace correct authenticator
   get("/:owner/:repository/pulls/compare/*:*...*")(referrersOnly { repository =>
     if(repository.repository.originUserName.isEmpty || repository.repository.originRepositoryName.isEmpty){
       NotFound // TODO BadRequest?
     } else {
-      val userName       = params("owner")
-      val repositoryName = params("repository")
-      val Seq(origin, originId, forkedId) = multiParams("splat")
+      getRepository(
+        repository.repository.originUserName.get,
+        repository.repository.originRepositoryName.get, baseUrl
+      ).map{ originRepository =>
 
-      JGitUtil.withGit(getRepositoryDir(userName, repositoryName)){ newGit =>
-        JGitUtil.withGit(getRepositoryDir(origin, repository.repository.originRepositoryName.get)){ oldGit =>
+        val Seq(origin, originId, forkedId) = multiParams("splat")
+
+        withGit(
+          getRepositoryDir(origin, repository.repository.originRepositoryName.get),
+          getRepositoryDir(params("owner"), params("repository"))
+        ){ (oldGit, newGit) =>
           val oldReader = oldGit.getRepository.newObjectReader
           val oldTreeIter = new CanonicalTreeParser
-          oldTreeIter.reset(oldReader, oldGit.getRepository.resolve("master^{tree}"))
+          oldTreeIter.reset(oldReader, oldGit.getRepository.resolve(s"${originId}^{tree}"))
 
           val newReader = newGit.getRepository.newObjectReader
           val newTreeIter = new CanonicalTreeParser
-          newTreeIter.reset(newReader, newGit.getRepository.resolve("master^{tree}"))
+          newTreeIter.reset(newReader, newGit.getRepository.resolve(s"${forkedId}^{tree}"))
 
           import scala.collection.JavaConverters._
           import util.Implicits._
@@ -61,9 +88,21 @@
 
           pulls.html.compare(commits.toList.splitWith{ (commit1, commit2) =>
             view.helpers.date(commit1.time) == view.helpers.date(commit2.time)
-          }, diffs.toList, origin, originId, forkedId, newId.getName, repository)
+          }, diffs.toList, origin, originId, forkedId, newId.getName, repository, originRepository)
         }
-      }
+      } getOrElse NotFound
     }
   })
+
+  private def withGit[T](oldDir: java.io.File, newDir: java.io.File)(action: (Git, Git) => T): T = {
+    val oldGit = Git.open(oldDir)
+    val newGit = Git.open(newDir)
+    try {
+      action(oldGit, newGit)
+    } finally {
+      oldGit.getRepository.close
+      newGit.getRepository.close
+    }
+  }
+
 }
diff --git a/src/main/scala/app/RepositoryViewerController.scala b/src/main/scala/app/RepositoryViewerController.scala
index 43cb126..e4dc1ed 100644
--- a/src/main/scala/app/RepositoryViewerController.scala
+++ b/src/main/scala/app/RepositoryViewerController.scala
@@ -218,7 +218,7 @@
       JGitUtil.withGit(getRepositoryDir(repository.owner, repository.name)){ git =>
         val revisions = Seq(if(revstr.isEmpty) repository.repository.defaultBranch else revstr, repository.branchList.head)
         // get specified commit
-        revisions.map { rev => (git.getRepository.resolve(rev), rev)}.find(_._1 != null).map { case (objectId, revision) =>
+      JGitUtil.getDefaultBranch(git, repository, revstr).map { case (objectId, revision) =>
           val revCommit = JGitUtil.getRevCommitFromId(git, objectId)
 
           // get files
diff --git a/src/main/scala/service/RepositoryService.scala b/src/main/scala/service/RepositoryService.scala
index d207f6d..4ec1651 100644
--- a/src/main/scala/service/RepositoryService.scala
+++ b/src/main/scala/service/RepositoryService.scala
@@ -185,6 +185,17 @@
     }
   }
 
+//  def getBaseRepositories(userName: String, repositoryName: String, repositories: List[String] = Nil): List[String] = {
+//    Query(Repositories).filter { t =>
+//      (t.originUserName is userName.bind) && (t.originRepositoryName is repositoryName.bind)
+//    }.map(_.userName).list match {
+//      case Nil  => repositories.sorted
+//      case list => list.map { x =>
+//        getBaseRepositories(x, repositoryName, x :: repositories)
+//      }.flatten
+//    }
+//  }
+
 }
 
 object RepositoryService {
diff --git a/src/main/scala/util/JGitUtil.scala b/src/main/scala/util/JGitUtil.scala
index b2ce900..747ca66 100644
--- a/src/main/scala/util/JGitUtil.scala
+++ b/src/main/scala/util/JGitUtil.scala
@@ -15,6 +15,7 @@
 import org.eclipse.jgit.errors.MissingObjectException
 import java.util.Date
 import org.eclipse.jgit.api.errors.NoHeadException
+import service.RepositoryService
 
 /**
  * Provides complex JGit operations.
@@ -419,7 +420,7 @@
         case true if(logs.size < 2) => getCommitLog(i, logs :+ i.next)
         case _ => logs
       }
-    
+
     val revWalk = new RevWalk(git.getRepository)
     revWalk.markStart(revWalk.parseCommit(git.getRepository.resolve(id)))
     
@@ -532,4 +533,14 @@
     config.save
   }
 
+  def getDefaultBranch(git: Git, repository: RepositoryService.RepositoryInfo,
+                       revstr: String = ""): Option[(ObjectId, String)] = {
+    Seq(
+      if(revstr.isEmpty) repository.repository.defaultBranch else revstr,
+      repository.branchList.head
+    ).map { rev =>
+      (git.getRepository.resolve(rev), rev)
+    }.find(_._1 != null)
+  }
+
 }
\ No newline at end of file
diff --git a/src/main/twirl/pulls/compare.scala.html b/src/main/twirl/pulls/compare.scala.html
index e3decca..8ea107a 100644
--- a/src/main/twirl/pulls/compare.scala.html
+++ b/src/main/twirl/pulls/compare.scala.html
@@ -1,13 +1,33 @@
 @(commits: Seq[Seq[util.JGitUtil.CommitInfo]], diffs: List[util.JGitUtil.DiffInfo],
   origin: String, originId: String, forkedId: String, commitId: String,
-  repository: service.RepositoryService.RepositoryInfo)(implicit context: app.Context)
+  repository: service.RepositoryService.RepositoryInfo,
+  originRepository: service.RepositoryService.RepositoryInfo)(implicit context: app.Context)
 @import context._
 @import view.helpers._
 @import org.eclipse.jgit.diff.DiffEntry.ChangeType
 @html.main("Pull Requests - " + repository.owner + "/" + repository.name){
   @html.header("pulls", repository)
   <div style="border: 1px solid #eee; background-color: #f8f8f8; margin-bottom: 10px; padding: 8px;">
-    <span class="label label-info monospace">@origin:@originId</span> ... <span class="label label-info monospace">@repository.owner:@forkedId</span>
+    <div id="compare-info">
+      <a href="#" id="edit-compare-condition" class="btn btn-mini pull-right">Edit</a>
+      <span class="label label-info monospace">@origin:@originId</span> ... <span class="label label-info monospace">@repository.owner:@forkedId</span>
+    </div>
+    <div id="compare-edit" style="display: none;">
+      <a href="#" id="refresh-compare" class="pull-right"><i class="icon-remove-circle"></i></a>
+      <span class="label label-info monospace">@origin/@repository.name:</span>
+      @helper.html.dropdown(originId) {
+        @originRepository.branchList.map { branch =>
+          <li><a href="#">@helper.html.checkicon(branch == originId) @branch</a></li>
+        }
+      }
+      ...
+      <span class="label label-info monospace">@repository.owner/@repository.name:</span>
+      @helper.html.dropdown(forkedId) {
+        @repository.branchList.map { branch =>
+          <li><a href="#">@helper.html.checkicon(branch == forkedId) @branch</a></li>
+        }
+      }
+    </div>
   </div>
   <div style="margin-bottom: 10px;">
     <a href="#" class="btn">Click to create a pull request for this comparison</a>
@@ -63,6 +83,15 @@
 }
 <script>
 $(function(){
+  $('#edit-compare-condition').click(function(){
+    $('#compare-info').hide();
+    $('#compare-edit').show();
+  });
+
+  $('#refresh-compare').click(function(){
+    // TODO send request
+  });
+
   $('#toggle-file-list').click(function(){
     $('#commit-file-list').toggle();
     if($(this).val() == 'Show file list'){