To date there have been no studies investigating the characteristics of pain in Chinese hero-independent patients (HDPs) receiving methadone maintenance treatment (MMT). This study examined the frequency and socio`-demographic and clinical correlates of pain in HDPs under MMT. A consecutive sample of 603 HDPs was recruited from three MMT clinics in Wuhan, China. These patients completed a standardized questionnaire concerning socio-demographic and clinical data. Pain intensity was assessed with the 5-point Verbal Rating Scale ("Overall, how intense is your pain now?") with responses of: 1=none, 2=mild, 3=moderate, 4=severe, 5=very severe. A pain score of three or higher was used to denote clinical significant pain (CSP). The prevalence of CSP in HDPs receiving MMT was 53.6%. Factors significantly associated CSP in multiple logistics regression analysis were old age, marital status of "non-married", unemployment, having religious beliefs, a history of injecting heroin, a high dose of methadone, and more depressive symptoms. Over a half of Chinese HDPs receiving MMT have CSP. Services for HDPs in MMT settings should include periodic screening for pain, psychosocial supports, and professional treatment for pain.