Although the number of patients receiving antiretroviral (ARV) therapy in Central China is expanding, little is known about their medication adherence. The purpose of this study was to: (1) describe adherence prevalence among patients receiving free ARV in south central China; (2) identify factors associated with adherence; (3) compare 3 self-report measures of adherence in this population. A cross-sectional survey was conducted at seven free treatment sites in Hunan, Hubei, and Anhui Provinces. Adherence measures included direct questioning regarding the number of doses taken in the 7 days prior to interview, the Community Programs for Clinical Research on AIDS (CPCRA) Adherence Self-Report questionnaire, and a 7-day visual analogue scale. Subjects comprised all patients returning for monthly ARV follow-up at each site between April and July 2006. Among the 308 subjects, 244 (79%) lived in the countryside. One hundred seventy (55%) had been on ARV over 1 year. No regimen included a protease inhibitor. Two hundred forty-four (80%) reported taking more than 90% of prescribed doses in the previous 7 days. Sixty-four (20%) subjects reported missing at least 1 dose in that period. The three measures of self-reported adherence were highly correlated. On multivariate analysis, current heroin use (odds ratio [OR] = 2.5; 95% confidence interval [CI] 1,6, p = 0.05) and nonuse of reminders such as cell phone alarms, wall charts, or TV programs (OR 6; 95% CI 3, 11; p = 0.001) were associated with 90% or less adherence. Adherence to ARV in Central China is similar to elsewhere in the world. The 20% of subjects who reported taking 90% or fewer doses are of concern in view of the potential for non-nucleoside reverse transcriptase inhibitor resistance and lack of protease inhibitor back-up regimens. Substance abuse treatment will be an essential element of successful AIDS treatment in China. Prospective studies are needed to evaluate the efficacy of reminder devices to improve adherence in this population and to describe the prevalence and incidence of ARV resistance.