OBJECTIVES: This study evaluated the validity of concerns about the toxicity of nevirapine (NVP) that have delayed its implementation as a perinatal HIV prevention strategy. METHODS: A decision analysis model compared 3 strategies: single-dose NVP, short-course zidovudine (ZDV), and no intervention. RESULTS: NVP would prevent more deaths than ZDV and no intervention as long as the rate of NVP toxicity did not exceed, respectively, 9 times that observed in the earlier NVP clinical trial and 42 times that observed in the clinical trial. NVP would be economically preferable to ZDV as long as the rate of toxicity did not exceed 22 times that observed in the clinical trial. CONCLUSIONS: Field implementation of NVP should not be delayed by concerns about its toxicity.