BACKGROUND Due to the shortage of organs for transplantation, there has been increased interest in developing living-donor kidney transplantation (LDKT) programs. MATERIAL AND METHODS A total of 668 potential living kidney donors (PLKD) for 496 intended recipients were evaluated in a LDKT program between 2010 and 2014. Causes for PLKD exclusion were recorded, as well as patient survival. RESULTS After evaluation, 250 (37.4%) PLKD were considered suitable for kidney donation, 331 (49.6%) were excluded for medical reasons, and 87 (13.0%) withdrew their consent. The main cause of exclusion was metabolic syndrome and its components: 131 (39.6%) obesity, 37 (11.2%) new diagnosis of diabetes mellitus, and 25 (7.6%) new diagnosis of hypertension. Sixty-three (19.0%) were excluded for previously undetected renal diseases. Forty-six (13.9%) PLKD were excluded for immunological incompatibility. A total of 158 patients (31.9%) were transplanted from living donors and 31 (6.3%) from deceased donors (after the donor was considered non-suitable). Three-year patient survival was 99.4% for transplanted patients and 41.4% for patients who remained on dialysis. CONCLUSIONS Metabolic diseases constitute the main cause of donor exclusion in some LDKT programs. The high mortality rate of patients whose donor is excluded renews the debate over expanding donor criteria against the long-term risks they may pose to the living kidney donor.