Microsatellite markers have been selected as the marker system of choice because of their low cost, high efficiency, whole genome coverage, robustness and minimum DNA requirements. In addition, they are highly polymorphic, co-dominant, PCR based and easily detectable. In common bean there are a range of microsatellite markers of which several sets of gene-based and genomic SSRs have been developed and mapped at CIAT. The aims of the CIAT program have been 1) to evaluate a large set of mapped SSRs for their diversity value (D), polymorphism information content (PIC) and heterozygosity level on a representative set of common bean genotypes and 2) to use the microsatellites in diversity assessment. This effort has been justified based on the need to select the most polymorphic markers for future analysis and apply them for germplasm characterization especially in the CIAT genebank and with National program partners.