In this study the effects of co-digestion of sewage sludge and food waste leachate on the anaerobic digestion efficiency from sewage treatment facilities in S. Korea were investigated. For this study 15 facilities were selected including 9facilities treating sewage sludge only (S-Only) and 6 facilities treating sewage sludge and food waste leachate (S-MIX). The average volatile solid (VS) removal rate of S-Only was 30.7% and that of S-MIX was 45.2%. The COD removal rate of S-MIX (61.3%) was higher than that of S-Only (48.6%). It has been observed that the anaerobic digestion efficiency of S-MIX was superior to that of S-Only because S-MIX contained more sufficient nutrient with higher VS contents and total solid (TS) contents emerging from food waste leachate. Therefore food waste leachate addition in sewage sludge anaerobic digestion would be the preferred option to treat only sewage sludge.