We report the step-by-step process of developing de novo microsatellite (SSR) loci in two Loxosceles spider species. We used reads obtained with next-generation sequencing (Roche 454) to select hundreds of potentially-amplifiable SSRs. After testing amplification and cross-amplification, we characterized 18 SSRs, 11 of which were polymorphic in Loxosceles rufescens (Dufour 1820) and seven of which were polymorphic in L. sp. Fuerteventura - Lanzarote. This method is a relatively fast and economic procedure for the development of fast-evolving nuclear markers in spiders.