The prevalence of upper and lower eyelid diseases of cats was evaluated, during two years in the Veterinary Teaching Hospital of the Buenos Aires University. The world wide reports indicate a low prevalence of these diseases. Three hundred and fifty cats with ocular problems were evaluated. The patients were mostly crossbreed (85%) and 15% of pure breed such as: Siamese, Persian, Oriental and Cornish. The eyelid diseases showed a prevalence of 29% of the total of patients with ocular conditions. Upper eyelid agenesis or eyelid coloboma was detected with a prevalence of 3.1%. All the cases (10 crossbred cats) evidenced a complete absence of the upper eyelid. Only two cats had bilateral condition and associated with other ocular congenital diseases. Entropion had a 11,4% of prevalence. Only 1,14% of them were primary entropion, in Siamese and Persian cats. The 40 cats affected required surgical procedures in order to obtain a normal margin of the eyelid and to preserve the large cornea of cats. The predominantly frequency of secondary entropion, mostly caused by chronic conjunctivitis and keratitis showed the importance of early detection of the primary etiology and specific treatment A 4.2% of patients showed lacerations which also required surgical corrections. The blepharitis was other eyelid condition detected in these patients with a prevalence of 6%. The etiology of blepharitis was: Demodex sp, mycotic infections, allergy, autoimmune diseases, myasis and adverse reactions to topical drugs. Eyelid tumors were 4.2% (15 cats) of the total patients. Eyelid tumors were most frequent on cats between 10 and 18 years of age. In contrast to eyelid neoplasia in dogs, eyelid tumors in cats are frequently malignant. The detected prevalence of the eyelid tumors in our patients resulted as follows: nine squamous cell carcinoma, two mast cell tumors, two lymphoma, one basal cell carcinoma and one fibrosarcoma. The treatment of these tumors was based on cryotherapy, conventional surgery and chemotherapy depending of histopathologic result and its aggressiveness and the time of evolution. The data collected in this article showed the prevalence of upper and lower eyelid diseases in a bias population because the Hospital works with referred patients. However the prevalence was higher than expected.