Ternary mutual diffusion coefficients measured by the Taylor dispersion method are reported for aqueous solutions of CaCl(2)-caffeine at carrier concentrations from (0.0025 to 0.0500) mol.dm(-3) for each solute, respectively. The results are compared with those obtained for the binary systems H(2)O-CaCl(2) and H(2)O-caffeine, also reported here. From these data, it is possible to make conclusions about the influence of the caffeine solutes in the diffusion of calcium chloride and to contribute to a better understanding of the structure of this system.