The objective of the study was to examine the effect of methadone maintenance treatement on mortality in people who inject opiods and who also recieve ART for the treatment of HIV in China. The study took place between December 3, 2002 and December 31, 2011. Mortality, disease and treatment characteristics were compared in patients who received either ART and MMT or only ART. Overall, mortaliy 6 months after starting ART was lwer with ART and MMT than with only ART. This study indicates that patients would benefit more from both MMT and HIV treatment programmes and would be faced with less barriers to care id there were cross-referrals between programmes and ART and MMT services were located together.