The pollen morphology of 13 taxa in the genus Potamogeton L. in Korea was investigated by light and scanning electron microscope. The pollen grains are monad, inaperturate and have a finely reticulate exine. Pollen grain was 18.25-35.50㎛ in maximal dimension of the grain(D), 16.60-27.83㎛ minimal diameter (d) and spherical or subprolate with 1.05-1.22 of D/d ratio. Pollen size was useful to distinguish each other in Potamogeton. The genus Potamogeton in Korea were divided by three groups by granule density of muri and pollen size. Beside, identification is possible in species level by pollen external morphology, pollen size, number of lumina, and number of columella. Detailed structure of pollen were useful to distinguish classification system of genus Potamogeton.