diff --git a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitLogCommand.java b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitLogCommand.java
index a6f74d24eb..bdbb87f2aa 100644
--- a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitLogCommand.java
+++ b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitLogCommand.java
@@ -49,6 +49,7 @@ import org.eclipse.jgit.treewalk.filter.PathFilter;
 import org.eclipse.jgit.treewalk.filter.TreeFilter;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import sonia.scm.NotFoundException;
 import sonia.scm.repository.Changeset;
 import sonia.scm.repository.ChangesetPagingResult;
 import sonia.scm.repository.GitChangesetConverter;
@@ -206,6 +207,9 @@ public class GitLogCommand extends AbstractGitCommand implements LogCommand
 
         if (!Strings.isNullOrEmpty(request.getAncestorChangeset())) {
           ancestorId = repository.resolve(request.getAncestorChangeset());
+          if (ancestorId == null) {
+            throw notFound(entity("Revision", request.getAncestorChangeset()).in(this.repository));
+          }
         }
 
         revWalk = new RevWalk(repository);
@@ -245,6 +249,8 @@ public class GitLogCommand extends AbstractGitCommand implements LogCommand
               break;
             }
           }
+        } else if (ancestorId != null) {
+          throw notFound(entity("Revision", request.getBranch()).in(this.repository));
         }
 
         if (branch != null) {
@@ -263,6 +269,10 @@ public class GitLogCommand extends AbstractGitCommand implements LogCommand
     {
       throw notFound(entity("Revision", e.getObjectId().getName()).in(repository));
     }
+    catch (NotFoundException e)
+    {
+      throw e;
+    }
     catch (Exception ex)
     {
       throw new InternalRepositoryException(repository, "could not create change log", ex);
diff --git a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitLogCommandAncestorTest.java b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitLogCommandAncestorTest.java
index d36922f941..a2bfa1bd36 100644
--- a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitLogCommandAncestorTest.java
+++ b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitLogCommandAncestorTest.java
@@ -35,6 +35,7 @@
 package sonia.scm.repository.spi;
 
 import org.junit.Test;
+import sonia.scm.NotFoundException;
 import sonia.scm.repository.ChangesetPagingResult;
 
 import static org.junit.Assert.assertEquals;
@@ -95,6 +96,28 @@ public class GitLogCommandAncestorTest extends AbstractGitCommandTestBase
     assertEquals("201ecc1131e6b99fb0a0fe9dcbc8c044383e1a07", result.getChangesets().get(6).getId());
   }
 
+  @Test(expected = NotFoundException.class)
+  public void testAncestorWithDeletedSourceBranch()
+  {
+    LogCommandRequest request = new LogCommandRequest();
+
+    request.setBranch("no_such_branch");
+    request.setAncestorChangeset("master");
+
+    createCommand().getChangesets(request);
+  }
+
+  @Test(expected = NotFoundException.class)
+  public void testAncestorWithDeletedAncestorBranch()
+  {
+    LogCommandRequest request = new LogCommandRequest();
+
+    request.setBranch("b");
+    request.setAncestorChangeset("no_such_branch");
+
+    createCommand().getChangesets(request);
+  }
+
   private GitLogCommand createCommand()
   {
     return new GitLogCommand(createContext(), repository);