This dissertation was prepared based on “publishable manuscripts” format of the Sokoine University of Agriculture. The dissertation discusses the composition and seasonal abundance of malaria vector species and disease prevalence in potentially high endemic foci in Morogoro region. Well targeted efforts that embrace area-specific situations, at least in high malaria endemic foci, are needed to preserve realized health gains and achieve elimination. This is because malaria is increasingly characterized by temporal variability that bestows evolving and new challenges for malaria control programs. Morogoro region, eastern Tanzania is a typical reflection of such phenomenon because of its appreciable fine-scale variability in ecology and topography. Therefore, it is likely that we are missing certain salient foci with unprecedented malaria transmission intensity. It was therefore critical to have up-to-date information on the species composition and abundance of malaria vectors; and disease prevalence in order to design and/or implement appropriate surveillance and control strategies. Mkuyuni and Kiroka, adjacent wards within Rural Morogoro District, are purported to form such foci and were therefore the focus of this study. The determination of malaria vector species composition and seasonal abundance was achieved through a repeated cross-sectional survey conducted during the wet and dry season. It involved collection of adult mosquitoes inside 10 randomly selected households and adjacent outdoor points using CDC light traps. This was accompanied by the assessment of environmental risk factors which could be potentiating malaria transmission risk. The prevalence of malaria in the study area was determined through a retrospective analysis of six-year (2014 - 2019) data on malaria cases. This study indicated that malaria vector population in study areas is largely composed of An. gambiae s.l followed by An. funestus s.l.; and their abundance is equally concerning across seasons. The study also revealed high malaria intensity in the study areas, with prevalence rate as high as ~61%. The mosquito species composition and equally concerning seasonal abundance all year round along with risk factors like open eaves, proximity to rice fields and low usage of bed nets could be among the factors that underline high malaria transmission in the study areas. These preliminary findings warrant more comprehensive longitudinal study in these and other high endemic foci in Tanzania in order to inform future course of action in terms of disease surveillance and control.