The denitrosation of MNTS  (N-methyl-N- nitroso-p-toluene sulphonamide) was studied in cationic micelles (CTAC1, CpyCl, CTABr, TTABr, LTABr, and OTAC1), cationic mixed micelles (LTA-OTA), nonionic micelles (POXCE), anionic micelles (HDS and SDS), cationic vesicles (DODAC) and cyclodextrin-cationic micelles mixed systems. The kinetic behaviour was explained on the basis of the pseudophase model, from which the binding constants of MNTS to different aggregates, the ion exchange constants, and the reactivity constants in the micellar pseudophase were obtained.