Mycobacterium tuberculosis infects one third of the world's population. Ethiopia ranks seventhrnin the world & third in Africa with TB prevalence. TB is the leading cause of morbidity, the thirdrncause of hospital admission and the second cause of hospital death in Ethiopia. TB patients takerndrugs for very long period of time. Hence, adherence is a major problem. To resolve this issue,rnthe World Health Organization recommends the strategy of Directly Observed Therapy-ShortrnCourse (DOTS) which includes Directly Observed Treatment (DOT) to ensure a better patientrnadherence. The observer may be a health worker or a trained and supervised community member.rnStudies elsewhere show varying results on the effectiveness of Community Based DOTrn(CBDOT) compared to Health Facility Based DOT (HBDOT) option. In Ethiopia, althoughrnattempts have been made to assess quality of DOT implementation, comparative effectiveness ofrnCBDOT versus HBDOT programs has not yet been assessed.rnThis study was conducted to assess effectiveness of DOT implementation in CBDOT andrnHBDOT program areas in Tigray region. The study also aimed to compare implementationrnpractice between the two DOT options and identify the factors affecting DOT implementation.rnThe study was a comparative cross sectional study conducted between October and December,rn2008. Both quantitative and qualitative methods were used for data collection. The quantitativernmethods used were retrospective review of Unit TB Registers avai lable in the health faci lities,rnprospective observation of DOT observers' practice, exit interview of TB patients and selfadministeredrnquestionnaire for health profess ionals. The qualitative method used was FocusrnGroup Discussions (FGD) for both groups.rnA total of 378 patients, 118 from Hintalo Wajirat (CBDOT) and 266 from Enderta (HBDOT)rnWoredas, registered from September 2005 to February 2008 treatment outcomes were reviewedrnretrospectively from Unit TB Registers. Effectiveness was measured by success rate. Treatmentrnwas successful for 101 (88.6%) and 181 (87.4%) new TB patients in CBDOT and HBDOTrnprogram areas, respectively. For new sputum smear positive pulmonary TB cases treatment wasrnsuccessful for 19 (90.5%) patients in CBDOT and 28 (84.8%) patients in HBDOT options.rnCBDOT option was as effective as HBDOT in treating TB patients and can achieve goodrntreatment outcomes. CBDOT option also reduced transfer out of TB patients.This study found out that DOT implementation as indicated by observation of DOT providerrnpractice was comparable for CBDOT and HBDOT program areas. This indicated that CBDOTrnobservers can practice DOT like HBDOT providers. Hence, CBDOT can complement HBDOTrnand could be a viable alternative in areas where people live faraway from health facilities.rnThe study also identified access, acceptability of DOT option and DOT providers, awareness ofrnpatients and providers, support to the patient, incentive to CBDOT providers, healthrnimprovement, documentation and supervision as factors that could affect DOT implementation.rnVoluntary Community Health Workers are available in each and every village and are willing tornrender service to their villagers. National/regional policy should be adopted to equip them withrnproper training and provide supportive supervision so that they tremendously increase bothrnaccess and quality of DOT. Mechanisms should be devised to ensure that health workers developrnsupportive attitude and facilitate wide scale deployment of voluntary Community Health Workers.rnKey words: TB, DOT, CBDOT, HBDOT, Effectiveness, Treatment success and Tigray