Trachoma, a recurrent follicular conjunctivitis caused by Chlamydia trachomatis, is the leading cause of preventable blindness worldwide. Efforts to control this disease have met with limited success. This failure is due in part to the limitations of conventional antibiotic treatment, a prolonged course of topical tetracycline. Azithromycin, an azalide antibiotic, is effective against chlamydial infections when given as a single oral dose. Recent research from Africa has shown azithromycin to be as effective as tetracycline in the treatment of trachoma. Under operational conditions azithromycin proved to be more effective. This success is attributed to a much-improved compliance with treatment. Community-wide mass treatment with azithromycin is advocated as a means of controlling trachoma in endemic countries. Questions still remain over the use of azithromycin for this purpose. The frequency and target population of mass distribution campaigns need to be defined. A few countries are beneficiaries of a philanthropic donation by the manufacturer of azithromycin, Pfizer Inc. However, in the absence of a drug donation programme the cost-effectiveness of this measure is unclear.