<sec id="st1"> <title>SETTING</title> DOTS is a key pillar of the global strategy to end tuberculosis (TB). </sec> <sec id="st2"> <title>OBJECTIVE</title> To assess the effectiveness of community-based compared with facility-based DOTS on TB treatment success rates in Namibia. </sec> <sec id="st3"> <title>METHODS</title> Annual TB treatment success, cure, completion and case notification rates were compared between 1996 and 2015 using interrupted time series analysis. The intervention was the upgrading by the Namibian government of the TB treatment strategy from facility-based to community-based DOTS in 2005. </sec> <sec id="st4"> <title>RESULTS</title> The mean annual treatment success rate during the pre-intervention period was 58.9% (range 46-66) and increased significantly to 81.3% (range 69-87) during the post-intervention period. Before the intervention, there was a non-significant increase (0.3%/year) in the annual treatment success rate. After the intervention, the annual treatment success rate increased abruptly by 12.9% (P < 0.001) and continued to increase by 1.1%/year thereafter. The treatment success rate seemed to have stagnated at ∼85% at the end of the observation period. </sec> <sec id="st5"> <title>CONCLUSION</title> Expanding facility-based DOTS to community-based DOTS increased annual treatment success rates significantly. However, the treatment success rate at the end of the observation period had stagnated below the targeted 95% success rate. </sec>.