In order to quantitatively rationalize kinetic micellar effects, structural information about the micellar reaction media is needed. But at the same time, from kinetic micellar effects on adequately chosen chemical reactions, one can obtain structural information on these reaction media. In this work it was shown that changes in the characteristics of micellar aggregates caused by the addition of organic solvents to micellar solutions are made evident through kinetic studies in water-organic solvent micellar solutions. Only organic solvents which remain mainly in the bulk phase of the micellar solution have been considered.