A progressive, apparently inherited corneal dystrophy is described in an inbred line of Manx cats. Initial changes in the cornea are seen at four months of age and characterized by anterior stromal edema. Progressive worsening of the condition produces severe bullous keratopathy with eventual breakdown of both epithelium and stroma. Light microscopic and ultrastructural studies in the advanced disease state revealed marked edema of the corneal stroma, disintegration of collagen material, and the formation of epithelial bullae. Ultrastructural evidence shows a normal endothelium to be present. The pathogenesis of this corneal dystrophy is not clear and further studies are underway.