The adoption of blended learning to widen access, reduce cost, and improve the quality of education is becoming prevalent in higher education in sub-Saharan Africa and Tanzania in particular. University of Dar es Salaam and the Open University of Tanzania offer various blended learning courses using Moodle system via regional centres scattered across the country. Despite the success of these courses, instructors’ support has been unsatisfactory and habitually ignored regardless of the fact that institutions have established IT Units to provide such services. This study investigated the effectiveness of instructors’ support services as a major success factor to the delivery of blended courses using mixed method design using questionnaire and semi- structured interviews from 65 instructors teaching blended learning courses at the University of Dar es Salaam and the Open University of Tanzania. The study revealed that lack of both technical and pedagogical support has been critical factors inhibiting instructors from facilitating blended courses effectively via the LMS. The findings from this study have a number of important lessons and implications for similar institutions running blended learning or wishing to implement blended learning specifically in sub-Saharan Africa.