Although blepharitis is one of the most common ocular disorders encountered in clinical practice, it may constitute a diagnostic and therapeutic enigma. Attempts to classify this disorder are difficult because of the complex mechanisms underlying its pathogenesis. Clinical and laboratory investigations have clearly established bacteria and meibomian gland abnormalities as major etiologic determinants. In addition, changes in tear film dynamics and underlying dermatologic abnormalities appear to contribute to pathogenesis. The clinical manifestations primarily occur along the lid margin, and the predominant symptoms are itching and burning. Currently there is no cure for this condition. In the case of staphylococcal blepharitis, for example, there is no long-term cure because patients are likely susceptible to the causative organism(s), and thus become reinfected. Therapy is aimed then at bringing the disease process under control. A therapeutic regimen consisting of lid hygiene, topical or systemic antibiotics, and tear replacement seems to be most effective in alleviating symptoms and maintaining disease control but requires prolonged treatment.