This investigation focused on weekly variations in cell density and volume of the dinoflagellate Noctiluca scintillans between March 2001 and January 2004 in the Dardanelles. March-June and October-December periods were excessive bloom periods. During the bloom periods the density of N. scintillans reached 2.20 × 105 cells L-1 with a volume of 1.32 × 1012 µm3 L-1. In addition to the high surface density, there was an increase in subsurface waters during the blooms. The bloom of N. scintillans, like that of diatom and other dinoflagellate blooms, was associated not only with eutrophication, but also with stable temperatures and salinities.