The second case is reported of renal failure in association with XY gonadal dysgenesis. The random association of these conditions appears unlikely. Recognition of a possible association is important because of potential fatality due to renal failure or gonadoblastoma in unrecognized cases. In groups at risk, follicle-stimulating hormone (FSH) studies are appropriate in cases of renal disease occurring in phenotypic prepubertal females; in women with XY gonadal dysgenesis, BUN and urinalysis should be studied.