ABSTRACTBeef or soy flavor of meat loaves containing 0, 15% soy flour or 15% soy concentrate were evaluated after cooking in microwave or in conventional ovens. Also, cooking time, cooking losses, fat and moisture content and thiamine retention were determined. Beef or soy flavor was significantly affected (P<0.01) by loaf type, but not by oven treatment. Loaves (960g) cooked electronically reached 74°C in 19 min and had consistently higher cooking losses than those cooked conventionally for 78 min. Substitution of 15% soy reduced cooking losses more in loaves cooked in electric than in microwave ovens. Soy had no effect on the fat content, but cooking had a significant (P<0.01) effect; i.e., 11.5% fat in electronically and 9.6% in conventionally cooked loaves. Thiamine retention was not affected by 15% soy substitution. The average thiamine content, regardless of treatment, was 0.09 mg/100g of the cooked loaves