Background:　Social　support　has　been　considered　one　of　the　most　important　factors　of　health-related　quality　of　life　(HRQoL)　evaluations　among　different　populations;　however,　few　studies　have　explored　the　relationships　of　both　received　and　perceived　social　support　to　HRQoL　among　patients　undergoing　methadone　maintenance　treatment　(MMT).　Thus,　the　purpose　of　this　cross-sectional　study　was　to　clarify　these　relationships.　Methods:　Participants　were　patients　admitted　at　the　two　largest　privately　and　publicly　funded　MMT　clinics　in　Xi＇an.　The　main　explanatory　variable　was　social　support,　both　received　(i.e.,　social　network　support　and　professional　support　services)　and　perceived　(Multidimensional　Scale　of　Perceived　Social　Support).　The　outcome　was　HRQoL,　which　was　evaluated　using　the　Short-Form　36　Health　Survey　version　2　(SF-36v2)　and　the　Quality　of　Life　Scale　for　Drug　Addicts　(QOL-DAv2.0).　We　carried　out　independent　samples　t-tests　and　multiple　linear　regression　analysis　to　examine　the　relationships　between　received　and　perceived　social　support　and　HRQoL.　Results:　The　study　findings　revealed　that　patients　with　good　social　support　had　significantly　higher　scores　on　the　SF-36v2　and　QOL-DAv2.0　(p　＜　0.05).　After　controlling　for　individual　characteristics,　the　significant　factors　predicting　HRQoL　were　good　family　relationships,　usually　communicating　with　others,　a　convenient　service　time,　appropriate　treatment　charges,　and　good　perceived　social　support　(p　＜　0.05).　Conclusions:　Our　results　suggest　that　received　and　perceived　social　support　influences　HRQoL　among　individuals　receiving　MMT.　Thus,　these　variables　should　be　considered　during　health　management　efforts　and　interventions　directed　at　this　patient　population.