Objectives. This study compared the use of new antiretroviral treatments across sociodemographic subgroups during the 3 years after the introduction of these treatments and examined diffusion of the therapies over time. Methods. Merged surveillance and claims data were used to examine use of protease inhibitors and non-nucleoside reverse transcriptase inhibitors (PI/NNRTIs) among New Jersey Medicaid beneficiaries with AI DS. Results. In 1996, there were sharp disparities in use of PI/NNRTI therapy among racial minorities and injection drug users, even after control for other patient characteristics. These gaps had decreased by 1998. Higher PI/NNRTI treatment rates were also observed among beneficiaries enrolled in a statewide HIV/AIDS-specific home- and community-based Medicaid waiver program. Conclusions. Even within a population of individuals similar in regard to health coverage, there were substantial sociodemographic differences in use of PI/NNRTIs during the early years after their introduction. These differences narrowed as new treatments became standard. Participation in a case-managed Medicaid waiver program seems to be associated with a more appropriate pattern of use. These results suggest a need to address nonfinancial barriers to care.