Thailand cucurbits germplasm has been set up by the collaboration between Rajamangala University of Technology Lanna and National Science and Technology Development Agency since 2007. To describe genetic diversity for germplasm management and to find standard markers that were most effective in detecting genetic differences in this germplasm array, 134 cucumber accessions of diverse origins were analyzed by 11 microsatellite markers. Some accessions showed more than two alleles for specific marker signifying that they are still segregating and not yet stable and thus are omitted from further analysis. Genetic relationships among these accessions were described and a dendrogram was drawn showing that cucumber accessions are clustered into 4 groups. The phenotypic variations and genetic relationships among these accessions are discussed. These results will be useful in selection of accessions as breeding materials for further cultivar improvement programs.