The study of micellar systems water + CTAB + phenol, as function of the concentration of the solutes and of the temperature, was realised by calorimetry, conductometry and rheology. These different techniques have allowed to characterise the formation of complexes. The presence of phenol located between head groups of the surfactant diminishes the repulsive forces existing between the cationic groups, favoring the formation of worm-like micelles. The entanglement of these micelles provides viscoelasticity with the increase of phenol concentration and solutions seem to be gelled when ratio R=[phenol]/ [CTAB] is close to 1/1, similar to the behavior of solutions of polymers. For larger ratio R, or at elevated temperature, solutions become fluid again, indicating the weakness of the worm-like micelles comparatively to polymers.