Although China's government is rapidly expanding access to antiretroviral therapy, little is known about barriers to adherence among Chinese HIV-infected patients, particularly among injection drug users. To better understand barriers to antiretroviral treatment adherence, we conducted a qualitative research study, using both focus group and key informant methods, among 36 HIV-positive men and women in Dali, in southwestern China. All interviews utilized semi-structured question guides and were conducted in Mandarin, audio-recorded and translated into English for analysis. The most commonly cited adherence challenges were stigma, including secondary stigma experienced by family members; mental health issues; and economic concerns, particularly related to finding and maintaining employment. Distinctive gender differences emerged, partly due to previous heroin use among male respondents. Optimizing adherence may require that antiretroviral therapy programs be linked to other services, including drug addiction treatment, mental health services and vocational treatment and support. HIV care and service providers and policy makers in China responsible for HIV treatment should be aware of these important barriers to adherence.