diff --git a/src/calibre/ebooks/__init__.py b/src/calibre/ebooks/__init__.py
index a9985e6480..d5651568fa 100644
--- a/src/calibre/ebooks/__init__.py
+++ b/src/calibre/ebooks/__init__.py
@@ -24,7 +24,7 @@ class DRMError(ValueError):
 
 BOOK_EXTENSIONS = ['lrf', 'rar', 'zip', 'rtf', 'lit', 'txt', 'htm', 'xhtm',
                    'html', 'xhtml', 'pdf', 'pdb', 'prc', 'mobi', 'azw', 'doc',
-                   'epub', 'fb2', 'djvu', 'lrx', 'cbr', 'cbz', 'oebzip',
+                   'epub', 'fb2', 'djvu', 'lrx', 'cbr', 'cbz', 'cbc', 'oebzip',
                    'rb', 'imp', 'odt', 'chm', 'tpz', 'azw1', 'pml']
 
 class HTMLRenderer(object):