Understanding oviposition behavior is important to behavioral and vector ecologists because of its potential use in developing vector control strategies for insect-borne infectious diseases. Our study compared the oviposition behaviors of Anopheles gambiae s.s mosquitoes from two different regions of East Africa, Mbita Point, Kenya and Ifakara, Tanzania. The work sought behavioral evidence for the presence of an olfactory cue that modulates oviposition behavior in these different regional strains of Anopheles gambiae s.s. Results demonstrated that the larval rearing water of the different mosquito strains produced a signal that yielded a positive oviposition response from Anopheles gambiae s.s. gravid females of the same region. This not only implies the presence of an olfactory determinant of oviposition but it also could be a model for how speciation could arise within related taxa of mosquitoes.