This study was aimed at testing the efficacy of stored-grain insects in increasing crude protein and other contents of raw and processed maize grain. Crude protein values increased with increasing culture duration and differed between the different maize substrates (raw kernels, cooked and dried kernels and coarsely broken raw kernels). Thus, raw maize particularly the coarsely broken type, seemed a preferred substrate where most insects produced highest amount of protein. Peak protein values of 216.4, 252.6, 221.1 and 209.1 g/kg of dry matter were respectively observed for Tribolium Castaneum, Cryptolestes ferrugineus, Rhizopartha dominica and Sitophilus Zeamais. Fat content of the insect-rich biomass followed a pattern similar to that of protein, while soluble carbohydrate was reduced with increase in culture duration, perhaps due to utilization by the insects.