Abstract: Higher plants accumulate large quantities of storage proteins in seeds as sources of nutrition for germination and early growth during seed maturation. Seed storage proteins are classified into four groups, albumins, globulins, prolamins and glutelins, on the basis of their solubility. During seed embryo development, prolamins form aggregates after being synthesized on the endoplasmic reticulum (ER) and bud to form a protein body and are deposited in it. Albumin, globulin and glutelin proteins are synthesized as large precursors on the ER and then are sorted into various vesicles according to their sorting signals. The precursors are transported into protein storage vacuoles (PSVs) by receptor- mediated sorting and/or aggregation sorting mechanisms. Finally, the precursors are processed into mature forms by vacuolar processing enzymes and are deposited in PSVs. All the processes of synthesis, sorting, transport and processing affect the quality and quantity of seed proteins. We give an overview of the classification, transport and processing of the seed storage proteins and the effects of these processes on the quantity and quality of seed proteins.