An ulcer is a damage of the cornea. Melting ulcer is a type of damage with the characteristic agressive course of disease. Regardless of cause of an ulcer, pathomechanism involves the dissolution of collagen of the corneal stroma, and for that exogenous or endogenous proteolytic enzymes are responsible. Treatment of this type of ulcer includes antibiotics and nonsteroidal anti-inflammatory drugs, as well as drugs that would cause the effect of the inhibition of proteolytic enzymes. Since the progression of the damage develops rapidly, drugs must be administered frequently. In this article I would like to present a case of this type of ulcer in my cat.