Lysinibacillus sphaericus (Ls) strains that produce insecticidal proteins show high activity against mosquito larvae. The most active of these is the binary (Bin) toxin that acts following ingestion and, after midgut processing and binding to specific receptors, provokes cytopathological effects and leads to larval death. Bin toxin displays specific action against some species of medical importance (e.g. Culex and Anopheles) and it is safe to non-target organisms. These features have led to the production of biolarvicides based on this bacterium and its effectiveness to control mosquito larvae has been widely related in the literature. The field utilisation of Ls has also shown that resistance could be selected among exposed populations and the mechanisms and genes involved in this process have been described. Management strategies can be successfully employed to avoid resistance and Ls can be used within integrated programmes as a selective and efficient agent to control mosquitoes.