This study was conducted to determine the optimal level of dried distiller grains with solubles (DDGS) from a common ethanol manufacturing facility and to determine the potential interactions between dietary DDGS and added fat on performance and carcass characteristics of growing and finishing pigs. It was found that pigs fed diets containing DDGS had a tendency for decreased average daily gain (ADG) and Average daily feed intake (ADFI) decreased linearly with DDGS level. However, the greatest reduction occurred between pigs fed 15 and 20% DDGS. Eficiency in gain improved when DDGS were included in the diet. There was no effect on loin depth and carcass weight and percentage yield decreased with increasing DDGS levels. Backfat and fat free lean index tended to decrease with increasing levels of DDGS in the diet. Therefore it is concluded that finishing pigs raised under commercial production conditions can be fed 10 to 15% DDGS before growth rate is compromised.