Of 60 surgically removed multicystic, dysplastic kidneys examined for the presence of nodular renal blastema only 1 (2 per cent) had blastematous elements. Of the 60 patients 35 were from the authors' personal series and they were examined in clinical detail. The results of this study and those in the literature are discussed in relation to the over-all management of the asymptomatic multicystic, dysplastic kidney.