The nonuniformities of graft (co)polymers have been analyzed using the probability generating functions and their moments. The nonuniformity is described by ratios of averages of molecular weights of the graft (co)polymers. The general feature of the nonuniformity of graft (co)polymers is that, with increasing degree of grafting and degree of polymerization of the backbone, the nonuniformity of a graft (co)polymer passes through a maximum and approaches more or less closely the nonuniformity of the backbone (co)polymer. The nonuniformities of graft (co)polymer are a function of the number- and weight-average degrees of polymerization of the backbone and grafts and are independent of the type of the degree-of-polymerization distribution. The nonuniformity depends markedly on the disparity in the molecular weights of monomer units of the backbone copolymer and the grafts if the graft copolymer has a small number of grafts per backbone, but the disparity effect gets smaller with increasing degree of polymerization of the backbone and fraction of graftable units.