Background: We investigated the hatchability rates of freshly laid Anopheles gambiae s.s. eggs in presence of thirdinstars larvae. These experiments were conducted using 30 eggs in larval densities of 20, 60 and 100 larvae inmicrocosms. These experiments were designed to evaluate the eggs hatchability in habitats with late larvae instarsof the same species (experimental) or no larvae at all (control). Freshly laid eggs of An.gambiae s.s. were washed inmicrocosms containing larvae of third instars in different three densities (20, 60 and 100) and likewise in controlmicrocosms (without larvae). Eggs hatchability was monitored twice daily until no more first instar larvae emerged.The numbers of first instars larvae were record ed daily and lost eggs were considered preyed upon by third instars.Findings: The findings of this study showed that egg hatchability was significantly influence d by larval density.Conclusion: The findings of this study suggest that presence of larvae in habitats may significantly reducehatchability of eggs.