This project was undertaken to determine whether centralization of histocompatibility laboratory services for renal transplants performed within eastern Pennsylvania could improve the efficiency of allograft allocation and short-term allograft function. A nonconcurrent cohort study was performed comparing renal allografts transplanted between September 15, 1993, and September 14, 1994, to those transplanted between September 15, 1994, and September 14, 1995. All allografts were procured and allocated by the Delaware Valley Transplant Program, the organ procurement agency in eastern Pennsylvania. Cold preservation time and delayed allograft function were used to measure efficiency of allograft allocation and short term allograft function, respectively. The mean cold preservation time was reduced from 25.08 hours to 20.68 hours (P < 0.001). The percentage of delayed allograft function was 19.9 and 17.4 for the pre- and postcentralization groups, respectively (P = 0.5). Therefore, centralization of histocompatibility tissue typing was a regionally effective process intervention for reducing cold preservation time without adversely impacting short-term graft function. The magnitude of this reduction varied between individual centers. Further investigation is required to determine the effect on long-term allograft function and system wide costs.