DNA microsatellites are ubiquitously present in eukaryotic genomes and represent a vast source of highly informative markers. We describe in this article a (GGC)n microsatellite which is widely distributed in eukaryotic genomes. Using polymerase chain reaction (PCR) techniques and DNA sequencing, we demonstrated for the first time in plant species that a (GGC)n microsatellite locus is moderately polymorphic. Six alleles are present at this locus in rice and length polymorphisms are caused by variation in the number of tandem GGC repeats. By scoring a backcross mapping population, we were able to demonstrate that this locus is stably inherited and does not link to any known RFLP markers on the rice RFLP map. Our results suggest that DNA microsatellites should be useful in plants for construction of genetic linkage maps, extension of the existing genetic linkage maps, linkage analysis of disease and pest resistance genes, and the study of population genetics.