diff --git a/lib/casclient/tickets/storage.rb b/lib/casclient/tickets/storage.rb
index 0ea4f656..cac7bfdc 100644
--- a/lib/casclient/tickets/storage.rb
+++ b/lib/casclient/tickets/storage.rb
@@ -113,7 +113,7 @@ def read_service_session_lookup(st)
 
           st = st.ticket if st.kind_of? ServiceTicket
           ssl_filename = filename_of_service_session_lookup(st)
-          return IO.read(ssl_filename) if File.exists?(ssl_filename)
+          return IO.read(ssl_filename) if File.exist?(ssl_filename)
         end
 
         # Removes a stored relationship between a ServiceTicket and a local
@@ -126,7 +126,7 @@ def cleanup_service_session_lookup(st)
 
           st = st.ticket if st.kind_of? ServiceTicket
           ssl_filename = filename_of_service_session_lookup(st)
-          File.delete(ssl_filename) if File.exists?(ssl_filename)
+          File.delete(ssl_filename) if File.exist?(ssl_filename)
         end
 
         def save_pgt_iou(pgt_iou, pgt)