Cholesterol embolization (CE) in renal allografts is a rare occurrence, the natural history and prognostic significance of which is poorly characterized. We studied the clinicopathologic features and outcome of the largest known series of CE in renal allografts and combined our cases with those in the literature. We identified renal allograft biopsies with CE from 1997 to September 2004 at University of Pittsburgh Medical Center (UPMC). All pathology material related to such biopsies were examined and correlated with clinical information to determine the most probable CE source. Among 5435 RAB, 19 from 12 cadaveric transplant recipients comprising 7 males and 5 females (median age=63 y) had CE. Donors consisted of 9 males and 2 females (median age=47 y). One donor's age and sex was unknown. The most probable CE source was recipient in 9 cases and donor in 3 cases. Five had acute renal failure without acute cellular rejection and 2 had CE-specific failed allografts. Of 19 RAB, the most frequent coexisting diagnosis was chronic allograft nephropathy (63%). The median follow-up time was 661 days. Combining UPMC and non-UPMC cases (n=37) revealed a statistically significant loss of grafts with donor-derived (P value=0.00459) and early CE (P value=0.00938). In renal allografts, CE most often correlated with recipient and donor atherosclerosis. It may present with acute renal failure, but usually not acute graft loss. Graft failure is significantly associated with donor-derived and early CE. Although its prognosis may be poor in the setting of primary nonfunction, prolonged graft survival may be seen.