Every year over two hundred million cases of malaria occur worldwide causing human death and suffering often in the poorest countries. Most people who die from malaria are children under five years of age. Malaria is caused by parasites spread by mosquitoes when they feed on human blood. Currently prevention methods include insecticides and anti-malarial drugs. The problem with both is the increasing resistance towards them by mosquitoes and parasites, respectively. Therefore other approaches need to be investigated to find new solutions to this problem. One such research area is paratransgenesis, the genetic modification of symbiotic microorganisms in the mosquitoes to produce anti-malaria parasite molecules. One bacterium identified as a potential candidate for paratransgenesis is Thorsellia anophelis. When this study started, only one Thorsellia isolate existed in the world. The aim of this study was therefore to retrieve more Thorsellia isolates from Kenyan mosquito and water samples. The samples were screened by PCR followed by bacterial culturing of positive samples, which resulted in 38 new Thorsellia isolates confirmed by DNA sequencing. The isolation of new Thorsellia species enables further investigation of the potential for their use in paratransgenesis with the aim of contributing to the prevention of malaria transmission.