Background: Predictors of adverse events (AE) associated with nevirapine use are needed to better understand reports of severe rash or liver enzyme elevation (LEE) in HIV+ women. Methodology: AE rates following ART initiation were retrospectively assessed in a multi-site cohort of 612 women. Predictors of onset of rash or LEE were determined using univariate and multivariate analyses. Principal Findings: Of 612 subjects, 152 (24.8%) initiated NVP-based regimens with 86 (56.6%) pregnant; 460 (75.2%) initiated non-NVP regimens with 67 (14.6%) pregnant. LEE: No significant difference was found between regimens in the development of new grade ≥ 2 LEE (p =0.885). Multivariate logistic regression demonstrated an increased likelihood of LEE with HCV co-infection (OR 2.502, 95% CI: 1.04 to 6, p= 0.040); pregnancy, NVP-based regimen, and baseline CD4 >250 cells/mm3 were not associated with this toxicity.Rash: NVP initiation was associated with rash after controlling for CD4 and pregnancy (OR 2.78; 95%CI: 1.14-6.76), as was baseline CD4.250 cells/mm3 when controlling for pregnancy and type of regimen (OR 2.68; 95% CI: 1.19-6.02 p=0.017).Conclusions: CD4 at initiation of therapy was a predictor of rash but not LEE with NVP use in HIV+ women. Pregnancy was not an independent risk factor for the development of AEs assessed. The findings from this study have significant implications for women of child-bearing age initiating NVP-based ART particularly in resource limited settings. This study sheds more confidence on the lack of LEE risk and the need to monitor rash with the use of this medication. © 2010 Aaron et al.