Delayed graft function (DGF) that results in inferior renal allograft outcome has been extensively studied after deceased donor and living related donor renal transplantation (Tx). The purpose of this study was to investigate the incidence and risk factors of DGF in living unrelated donor (LURD) renal Tx recipients. Between March 1999 and March 2006, a total of 689 LURD renal Txs were performed at our center, 429 (62.3%) of recipients were male, 260 (37.7%) were female and 596 (86.5%) of donors were male, 93 (13.5%) were female. 50 (7.2%) of Txs were second Tx. 59 (8.6%) of allografts had multiple arteries. 53 of 689 recipients required dialysis within the first week after renal Tx so were defined to have DGF (incidence 7.7%). The characteristics of these 53 cases with DGF and 636 cases without it were compared by univariate and multivariate analysis models. In univariate analysis the female gender of kidney donor (P= 0.027), renal allograft with multiple arteries (P= 0.012) and retransplantation (P< 0.005) were significant risk factors for development of DGF. But donors' age and weight, recipients' age, gender, weight, years on dialysis, causes of renal failure and warm ischemia time were not significant risk factors for DGF. High panel reactive antibodies was more common in recipients with DGF (P= 0.09), however, it was not statistically significant. By multivariate analysis only significant risk factor for development of DGF was retransplantatoin (P= 0.02).