Dynamic light scattering was used to measure the translational diffusion coefficient of neutral diisobutyl zinc dithiophosphate in hexane. The experimental data were then analyzed using the method of cumulant, expansion (1) and CONTIN (2), (3). Translational diffusion coefficients were obtained and compared with the predictions of stick (4), (5) diffusion theory. The stick calculations approximated the shape of the molecules as ellipsoids (6), (7) and cylinders (4). Assumed, diameters of 10 angstroms in the ellipsoidal case and 7.5 angstroms in the cylindrical case were used in these calculations.