Clinicians treating concurrent gonococcal and chlamydial infections have a variety of drugs to choose from. Neisseria gonorrhoeae is adept at developing resistance and the choice of antibiotic must be dictated to some extent by the patterns of resistance in the locality of the clinician. In contrast, resistance of Chlamydia trachomatis to some classes of drugs has been shown in vitro but does not appear to be clinically important at present. The success of treatment depends on patient compliance with the drug administration schedule. With these organisms, which can be carried asymptomatically, many patients are unlikely to comply with courses of antibiotics. Although single-dose therapy with azithromycin is available and established for chlamydial genital infection, it is more expensive and difficult to justify in a cash limited Healthcare system, and its efficacy for treating concurrent gonococcal infection requires further study. In patients where compliance is likely to be of concern, its use may be justified. Another major deterrent for completing antibiotic courses is the adverse effect profile. Most of the available drugs cause only minor adverse effects, in particular gastrointestinal. Ofloxacin has a better profile than doxycycline but is considerably more expensive. Newer fluoroquinolones, found to be effective in vitro, are being assessed in clinical studies. However, more evidence is required before recommending these over the tried and tested therapies.