The distributions of inorganic nutrients and phytoplankton chlorophyll-a were investigated in relation to the hydrography of the Aegean Sea. The data were collected during cruises in May and October 1992, February, May and October 1993 and July 1994, in the framework of a National Marine Measurement and Monitoring Programme for the Aegean Sea. Concentrations of nitrate +nitrite+ammonia nitrogen and phosphate phosphorus were lower than those previously reported for the Black Sea; generally lowest at the surface, they increased with depth. The highest nutrient values were in the northern part of the Aegean Sea, and may have resulted from water originating from the Black Sea. Both phosphates and silicates increased with depth to maxima of 0.16 and 4.7 mu M, respectively. The concentration of chlorophyll-a ranged from 0.03 to 0.70 mg m(-3). Elemental ratios (N/P and Si/P) were calculated to be 13.6 - 36.8 and 14.0 - 48.0, respectively.