During the first two weeks of December 1985, measurements of the wind stress, the three-component wind speed variances, and the vertical flux of sensible heat were collected from a research platform in the North Sea. Obtained using a sonic anemometer, the turbulence data represent an extensive range of wind speed conditions (5--30 m/s), and the air-sea temperature difference was observed to span from -3¿ to +3¿ C. The data were collected from a boom extending 17 m to the west of the North Sea Platform at 33 m above the water surface. The results indicated that the 10-m-height neutral drag coefficient, CDN, exhibited a strong dependence on wave age, i.e., CDN was larger for growing waves than for steady state or decaying sea. The normalized turbulence statistics were found to corroborate the results of Smith (1980) and Large and Pond (1981). ¿ American Geophysical Union 1987