Brazil is the world's largest producer of common beans (Phaseolus vulgaris L.), which are one of the most widely consumed grain legumes in the world. Seven improved genotypes of dry, coloured, Brazilian common beans were analysed for their nutritional (chemical composition, oligosaccharides, phenolic compounds and antioxidant capacity) and protein quality (amino acid profile, amino acid score, trypsin inhibitor activity and in vitro protein digestibility). The grain bean cultivars studied showed a high content of fibre, with some aromatic amino acids present at higher levels than the Food and Agriculture Organization reference protein. The dry beans had intermediate protein digestibility, ranging from 50.3% in the BRS Notável cultivar to 66.9% in the Jalo Precoce cultivar. The studied dry beans contained anti-nutritional and flatulence factors, such as trypsin inhibitors and oligosaccharides. However, total phenolic compounds and antioxidant activity were high. Improved grain beans have important nutritional characteristics that need to be preserved, and some negative, anti-nutritional characteristics. The results presented in this study can be used to assist the identification of appropriate processing techniques that maintain the positive features of dry beans and eliminate their negative attributes.