Ten microsatellites were isolated from a genomic DNA library generated from guppy ("Poecilia reticulata; Poecilidae") enriched for C A-repeats. All of the 10 m icrosatellites were polymorphic in guppy with an average allele number of 4.9/locus ranging from 2 to 14. All 10-prim er pairs amplified specific products in green swordtail ("Xiphophorus helleri") and 9 of the 10 microsatellites displayed polymorphism (average allele number: 4.1/locus with a scope between 2 and 8). Size range of alleles at most loci were similar between the two fish species. These microsatellites could be applied to breeding programs performed on these two species and possibly other poecilids and to genetic and ecological studies.