The provision of HIV education and testing in substance use disorder (SUD) treatment programs is an important public health strategy for reducing HIV incidence. For many at-risk individuals, SUD treatment represents the primary point of access for testing and receiving HIV-related services. This study uses two waves of nationally representative data of 265 privately-funded SUD treatment programs in the U.S. to examine organizational and patient characteristics associated with offering a dedicated HIV/AIDS treatment track, onsite HIV/AIDS support groups, and onsite HIV testing. Our longitudinal analysis indicated that the majority of treatment programs reported providing education and prevention services but there was a small, yet significant, decline in the number of programs providing these services. Programs placed more of an emphasis on providing information on the transmission of HIV rather than on acquiring risk reduction skills. There was a notable and significant increase (from 26.0% to 31.7%) in programs that offered onsite HIV testing, including rapid HIV testing, and an increase in the percentage of patients who received testing in the programs. Larger programs were more likely to offer a dedicated HIV/AIDS treatment track and to offer onsite HIV/AIDS support groups, while accredited programs and programs with a medical infrastructure were more likely to provide HIV testing. The percentage of injection drug users was positively linked to the availability of specialized HIV/AIDS tracks and HIV/AIDS support groups, and the percentage of female clients was associated with the availability of onsite support groups. The odds of offering HIV/AIDS support groups were also greater in programs that had a dedicated LGBT track. The findings suggest that access to hospitals and medical care services is an effective way to facilitate adoption of HIV services and that programs are providing a needed service among a group of patients who have a heightened risk of HIV transmission. Nonetheless, the fact that fewer than one third of programs offered onsite testing, and, of the programs ones that do, fewer than one third of patients received testing, raises concern in light of federal guidelines.