The effect of renal transplantation on sexual performance was studied by means of a 47-item questionnaire. Data concerning sexual functioning prior to uremia, during treatment with maintenance hemodialysis, and following renal transplantation were obtained from 20 male and 17 female patients, all of whom had excellent function of their renal transplants. Maintenance hemodialysis was associated with a decline in sexual performance for almost all of the variables examined in both males and females. Successful renal transplantation generally afforded some improvement in sexual functioning although in most cases the preillness level of performance was not regained. Although the overall effects of maintenance hemodialysis and renal transplantation appeared similar for both males and females, examination of the specific pattern and extent of the effects revealed a number of differences. The most striking difference was that observed in the frequency of sexual intercourse. Both males and females reported a significant decline (p <.05) in this variable following the onset of maintenance hemodialysis. Males did note a significant increase (p <.05) in the frequency of intercourse following successful renal transplantation although this was still significantly lower than their preillness level (p <.05). Females, however, did not experience any significant increase in the frequency of intercourse following renal transplantation. Indeed, the women experienced a further diminution in the frequency of intercourse albeit not to a significant degree. The persistent sexual dysfunction of renal transplant recipients can probably be best understood as a complex phenomenon which involves various combinations of psychopathological and pathophysiological elements which are not completely ameliorated even with a successful renal transplant. © 1978 by The Williams & Wilkins Co.