It is well known that fibrin deposition in Bowman's space in association with crescent formation may play an important role in progressive glomerular injury in crescentic glomerulonephritis. Recent reports describe the presence of a procoagulant activity (PCA) in the glomeruli and its increased expression in human and experimental nephritis. The cells that synthesize PCA have not yet been identified. We attempted to determine if glomerular epithelial cells (GEC), one of the prominent cell populations in the crescent, can produce PCA. The PCA of cultured rat GEC was measured by clotting and amidolytic assays. The cultured GEC yielded PCA with the characteristics of a tissue factor, and this PCA was stimulated by interleukin 1, tumour necrosis factor-alpha, and lipopolysaccharide. We concluded that GEC produce tissue-factor-like PCA and thereby may contribute to fibrin deposition, which, along with macrophage or monocyte infiltration, leads to crescent formation in crescentic glomerulonephritis.