Brownian dynamics simulations are used to study the effect of the volume fraction of internal phase (10(-5) less than or equal to phi less than or equal to 0.40) on the flocculation rate (k(f)) of oil in water (O/W) emulsions. To cover the typical range of Hamaker constants, its characteristic value for a bitumen emulsion (A = 1.24 x 10(-19) J) and its typical order of magnitude for a latex dispersion (A = 1.24 x 10(-21) J) were used. Account of hydrodynamic interactions was made, using a new methodology [Urbina-Villalba et al. Phys. Rev. E 2003, 68, 061408], which incorporates local volume fraction corrections at intermediate separations, and exact hydrodynamic interactions at closer distances. The resulting flocculation rates and their half-lifetimes (t(1/2)) were analyzed as a function of the volume fraction and the initial mean free path (1) between the drops. Useful approximate relations are found for a limited range of volume fractions. Despite the fact that phi and l(-2) are related and t(1/2) should decrease with either one, while k(f) is expected to increase, the quality of the fittings was different, depending on the Hamaker constant and the variable chosen. For A = 1.24 x 10(-21) J, the best correlation involves t(1/2) and phi. In the case of A = 1.24 x 10(-19) J, the best fits contain k(f) and either phi or l(-2). In general, the flocculation rate decreases monotonically as the volume fraction lowers, approaching the theoretical estimation. Values of k(f) below the theoretical prediction, as those occasionally found in experimental evaluations of very dilute systems, were not observed.