Dot-blot hybridization with cloned genomic DNA labeled with photobiotin as a probe is used to detect Plasmodium falciparum sporozoites in dried mosquitoes. The assay is sensitive enough to detect 2 pg Plasmodium parasite DNA, or one infected mosquito in a pool of 40 insects using DNA extraction samples, or one infected mosquito in a pool of 25 insects without DNA extraction. A single mosquito squashed directly on a nitrocellulose filter for the determination of parasites provides a simple method for the detection of sporozoites. The mosquitoes triturated in reduction buffer were efficient for the screening of malaria infection of mosquitoes in a large number of samples. The species specificity, sensitivity, and ease of performance of this assay as well as the stability of the reagents may make it a useful epidemiological tool.