Oviposition and larval development of Tribolium castaneum (Herbst) and Cryptolestes ferrugineus (Stephens) were used as criteria of the nutritional value of 28 ground or 29 ball-milled cultivars of two-rowed barley, six-rowed barley, oat, triticale, durum and common wheat for these insects. Oviposition by individual adult T. castaneum, on 28 ground cultivars, was lowest only on Benito wheat and all oat except Terra (hulless). On 29 ball-milled cultivars, Coulter and Medora durum wheat were optimal for egg production while the least number of eggs was produced on Glenlea (wheat), TR 212 and 219 (two-rowed barley), Bonanza and Conquest (six-rowed barley) and all oat. Oviposition by C. ferrugineus on ball-milled cultivars was also optimal on durum wheat and was lowest on all oat. The pattern of egg laying for both species over three 4-d periods varied with the payability and texture of the ground and ball-milled cultivars. Rate of larval development for T. castaneum on three ball-milled oat and three durum wheat cultivars was slower on oat than on durum wheat and C. ferrugineus larvae rarely survived on oat; there were no significant differences among the cultivars of a crop. Environmental indices based on time to pupation and oviposition indicated the relative nutritive value of the various cereals and cultivars to both insect species.Key words: Oviposition, development, Ball-milled, Cereal, Tribolium castaneum, Cryptolestes ferrugineus