evidence: This cross-sectional study determined the prevalence, intensity of infection and geographical distribution of schistosome and STH infections among 4,065 children aged 5–19 years in 84 primary schools in Mbita and nearby islands of Lake Victoria (Mfangano, Ringiti, Rusinga and Takawiri), in western Kenya. Single stool samples were collected and examined for eggs of Schistosoma mansoni and STHs (Hookworms, Ascaris lumbricoides and Trichuris trichiura) using the Kato-Katz technique. Primary schools were mapped using geographical information system data on PDAs and prevalence maps generated using ArcView GIS software. [...] The objective of this cross-sectional study was to determine the prevalence, intensity of infection and geographical distribution of schistosome and STH infections among primary school children in Mbita and surrounding Islands of Lake Victoria (Mfangano, Ringiti, Rusinga and Takawiri) in western Kenya. Understanding the prevalence and distribution of infection in such endemic areas not only serves as a guide in pin-pointing high-risk populations and transmission sites which is critical in developing sound and targeted control interventions to reduce the burden of these infections, but also to provide a robust baseline to monitor program impact.