The seed coat ultrastructure of the genus Astragalus L. section Uliginosi Gray in Turkey was examined by Light Microscopy and Transmission Electron Microscopy in order to determine cytological features of two species and to contribute to their taxonomy. The macrosclereid, osteosclereid and parenchymatic cell layers are found to be in the seed coats. Testa is composed of a quite long, 2-3 layered, with tannin in vacuoles and thick walled macrosclereid cells, underneath there is a single osteosclereid layer with large intercellular space cells. The bottom layer consists of parenchymatic cells stored with starch grains, protein and lipid. The seed coat of these species is similar in structure; but the thickness of the layers is different. In all seed coat layers, A. odoratus is thicker than the A. falcatus.