The number of HIV-infected patients who are newly exposed to nevirapine is increasing worldwide. To minimize toxicity, clinicians must adhere to dosing guidelines, avoid prescribing the drug in patients with known increased risk of toxicity, and promptly recognize toxicities, which are mainly cutaneous and hepatic. These toxicities are more common with nevirapine than with efavirenz. Women with CD4 counts>250 cells/mm3 have particularly increased susceptibility to nevirapine toxicity. Improved understanding of the pathogenesis of nevirapine toxicity, and its relationship with pharmacokinetic parameters, genetic factors and cellular immune kinetics will enhance our ability to reduce the risk to the HIV-infected individual.