According to current research in many countries there were studies showing effectiveness of MMT programs in drug use prevention, but there is no data on effectiveness and cost-effectiveness of MMT in Lithuania. There are hard political discussions about feasibility and needs of such harm reduction and drug prevention programs also this is associated to intentions to finance such maintenance programs from the state health care budget. Aim - we aimed to analyze economic effectiveness of six month methadone maintenance treatment program in Lithuanian primary health care setting. Objectives 1. To analyze effectiveness of methadone maintenance program and quality of life changes during program implementation. 2. To account costs for methadone maintenance program in Lithuania. 3. To analyze cost – utility of methadone maintenance program and to compare results with available data from other analogical studies.