Scleroderma renal crisis is irreversible in some patients despite aggressive treatment. This study was designed to identify pathologic prognostic features in scleroderma renal crisis. We retrospectively reviewed the pathology and the clinical records of 17 patients who underwent kidney biopsies during scleroderma renal crisis (group A, recovered renal function [n = 7]; group B, remained in renal failure or died [n = 10]). Multiple histologic features were assessed semiquantitatively (0-3) or as percentages. C4d staining of peritubular capillaries and small vessels was assessed semiquantitatively (0-3) in patients with scleroderma (n = 11), normotensive (n = 10), and hypertensive (n = 12) nonscleroderma native kidney controls. The percentage of thrombosed vessels (25.1 +/- 21.0 versus 5.6 +/- 12.3, P = .045) and the severity of glomerular ischemic collapse (2.9 +/- 0.3 versus 1.4 +/- 0.8, P = .001) were significantly higher in group B than in group A. Also, group B patients tended to have more severe acute tubular injury and vascular fibrinoid changes. The peritubular capillary C4d score in patients with scleroderma, normotensive controls, and hypertensive controls were 1.1 +/- 0.9, 0.3 +/- 0.7, and 0.3 +/- 0.5, respectively (P = .018, scleroderma versus other controls). Small vessel C4d score was higher in scleroderma compared to normotensive but not hypertensive controls. Within scleroderma samples, a significantly higher peritubular capillary C4d score (1.6 +/- 0.7 versus 0.3 +/- 0.5, P = .024) but not small vessel score was found in group B compared to group A. This tended to be associated with peritubular capillary leukocyte margination. Vascular thrombosis, severe glomerular ischemic collapse, and peritubular capillary C4d deposits in scleroderma renal crisis kidney biopsies correlated with increased risk of failure to recover renal function.