The Renal Unit of Obafemi Awolowo University Teaching Hospital Ile-Ife in Southwest Nigeria intends commencing a kidney transplantation program. This cross-sectional study aimed at examining the willingness of Nigerians to be living-related kidney donors. Three hundred and sixteen Nigerians (96 first-degree relatives of end-stage renal disease patients, 69 rural dwellers and 151 health workers) were interviewed regarding their willingness to donate kidneys using an interview schedule designed to elicit socio-demographic information, knowledge about kidney transplantation and attitude toward kidney donation. Sixty-two percent of health workers, 52.1% of the patients' relatives and 27.1% of rural dwellers expressed willingness to donate. Higher proportions of health workers and patients' relatives--compared with the rural dwellers--were willing to donate a kidney to their children, full-siblings and parents (P<0.05). The level of awareness about kidney transplantation was highest among health workers and least among rural dwellers (P<0.001). Altruism was the primary motivation for those willing to donate a kidney. The most important reason for refusal to donate was fear of adverse health consequences. Among the rural dwellers, never-married persons were more willing than the married to donate (P<0.05). Programs aimed at increasing awareness about the safety of kidney donation, reducing adverse beliefs about kidney donation, and encouraging altruistic tendencies will increase the availability of kidney donors.