This study examines the diffusion coefficients of cuprous and cupric ions in aqueous solutions containing 4-6 mol.dm(-3) bromide ion. Under these conditions, the majority of the Cu2+ species is the complex CuBr(4)(-)2, and the majority of Cu+ species is the complex CuBr3-2. Diffusion coefficients were obtained for temperatures ranging from 298 to 334 K via a rotating disk electrode and the Levich relationship. Diffusion coefficients for the cuprous bromide complex were found to be between 11.9 and 19.1 X 10(-6) cm(2).s(-1). Diffusion coefficients for the cupric bromide complex ranged between 4.5 and 12.0 X 10(-6) cm(2).s(-1). Confidence intervals were calculated with reasonable uncertainties. The diffusion coefficients were found to be in good agreement with literature values of cuprous and cupric chloride complexes.