The complexity of small-scale density fluctuations is investigated experimentally, with special emphasis on their scale-similar (fractal) facets. Using empirical observations, it is shown that the fractal dimension of density at scales between 0.1 and 3 m is closely related to the turbulent kinetic dissipation rate &egr;, the local buoyancy frequency N, and the buoyancy Reynolds number &egr;/&ngr;N2 in the upper equatorial Pacific thermocline. ¿ American Geophysical Union 1996