The Lafayette and Elizabeth Rivers flow into the waters of Hampton Roads, Virginia, where they meet the James River on its course to the lower Chesapeake Bay. The western and eastern branches of the Elizabeth River represent inter-tidal waterways that join this river near its mouth. Pritchard (1952) has described the water movements of the James River estuary and the phytoplankton investigations have been reviewed by Marshall (1967a). The purpose of this study is to present observations on the phytoplankton composition of the Lafeyette River, and the western and eastern branches of the Elizabeth River.