The subject is reviewed under the following headings: what is quality?; characteristics of cereal seed proteins; increasing protein content; improving protein composition by conventional and mutation breeding (seed protein mutants; progress in breeding with protein mutants; and free amino acid mutants); background to the genetic engineering of cereals (limitations to the genetic engineering of cereals; and current knowledge of plant gene structure and regulation); barley seed proteins: a case study in genetic engineering (prolamins; 7S and 11S globulins; and lysine-rich minor storage proteins); and future prospects