Roxithromycin is a derivative of the macrolide antibacterial erythromycin with in vitro antibacterial activity resembling that of the parent compound. The drug has activity against some Staphylococcus spp., many Streptococcus spp., Moraxella (Branhamella) catarrhalis, Mycoplasma pneumoniae, Legionella pneumophila and Chlamydia trachomatis as well as many less common organisms. Measured using recently proposed guidelines, roxithromycin has in vitro activity against Haemophilus influenzae. In comparison with that of its parent compound, the pharmacokinetic profile of roxithromycin is characterised by high plasma, tissue and body fluid concentrations and a long half-life permitting an extended dosage interval. Roxithromycin has proven clinical efficacy in upper and lower respiratory infections, skin and soft tissue infections, urogenital infections and orodental infections, and appears to be as effective as more established treatments including erythromycin, amoxicillin/clavulanic acid and cefaclor. The drug has also shown promise in a variety of more specialised indications including opportunistic infections in human immunodeficiency virus (HIV)-positive patients and as part of a Helicobacter pylori eradication regimen. Roxithromycin is very well tolerated with an overall incidence of adverse events of approximately 4%. Thus, roxithromycin is an attractive therapeutic alternative in its established indications, especially when the option of once-daily administration is considered.