Feed conversion efficiency contributes directly or indirectly on the cost benefit ratio of silkworm rearing and is considered to be an important physiological criterion for evaluating the superiority of silkworm breeds/hybrids. Food intake, assimilation and conversion of indigenous as well as exotic silkworm races are well studied by many researchers. In this review, an attempt has been made to consolidate works on feed conversion aspects of indigenous and exotic silkworm races. The paper also deals with the effect of various factors viz., nutritional, environmental and feeding on food assimilation and conversion parameters of mulberry silkworm.