diff --git a/lib/google_cells/revision.rb b/lib/google_cells/revision.rb
index fc980f5..e8ee681 100644
--- a/lib/google_cells/revision.rb
+++ b/lib/google_cells/revision.rb
@@ -29,7 +29,7 @@ def spreadsheet
     def self.parse_from_entry(entry)
       author = entry['lastModifyingUser']
       { id: entry['id'],
-        updated_at: entry['modifiedDate'],
+        updated_at: Time.parse(entry['modifiedDate']),
         etag: entry['etag'],
         author: (author.nil? ? nil : Author.new(
           name: author['displayName'],
diff --git a/spec/google_cells/revision_spec.rb b/spec/google_cells/revision_spec.rb
index 2f3187b..b3f700c 100644
--- a/spec/google_cells/revision_spec.rb
+++ b/spec/google_cells/revision_spec.rb
@@ -26,7 +26,7 @@
       r = revisions.last
       r.id.should eq "22"
       r.etag.should be
-      r.updated_at.should be
+      r.updated_at.should be_a Time
       r.spreadsheet_key.should be
     end