We have examined the possible expression of fibroblast growth factor in cultured cells derived from bovine lens epithelium and corneal endothelium. Lens epithelial, but not corneal endothelial, cells were found to express the acidic fibroblast growth factor (aFGF) gene, whereas both cell types express the gene encoding basic fibroblast growth factor (bFGF), a related mitogen. Expression of bFGF was further examined. Both corneal endothelial and lens epithelial contain 3.7 and 7.0 k bFGF gene transcript, which are translated into material closely related, if not identical with bFGF. Essentially all of the bFGF-like material is bioactive, i.e. it can stimulate the proliferation of capillary endothelial or corneal endothelial cells and the stimulation is blocked by anti-bFGF antibodies. Our results indicate that bFGF derived from corneal endothelial and lens epithelial cells may act as a paracrine and autocrine growth factor in both cell types. Thus, bFGF present in both cell types may play an important role in the proliferation of injured or transformed ocular tissues.