There are various reports in the literature regarding the effects of age and sex matching of donors and recipients on short and long term outcomes of organ transplantation. This study aimed to investigate the effects of age and sex matching on patient and graft survival in kidney transplant recipients.In a retrospective study in Baqiyatallah Hospital (Tehran, Iran) between the years 1993 and 2005, 2649 records of first kidney transplantations were reviewed. Based on age, donors (D) and recipients (R) were divided into four age groups as follows: group I (R<40, D<40), group II (R>40, D<40), group III (R<40, D>40) and group IV (R>40, D>40). With regard to gender, they were also categorized into four groups: group I (R: female, D: female), group II (R: male, D: male), group III (R: female, D: male) and group IV (R: male, D: female). Age and sex groups were compared with respect to 5-year graft and patient outcomes. Graft survival in four age groups was 70%, 73%, 37% and 43%, respectively (p=0.001). Patient survival in age groups was 89%, 84%, 55% and 55%, respectively (p=0.001). Graft survival in four sex groups was 73%, 70%, 73% and 51%, respectively (p=0.022). Patient survival in sex groups was 90%, 87%, 88% and 68%, respectively (p=0.003). This study confirms the concomitant effect of age and gender of donors and recipients on the outcomes of transplantation. It is necessary that future survival studies of organ transplantation, consider matching of demographic variables of donors as well as recipients.