This work reports the systematic study of surface phenomenon and self-aggregation behavior of cationic surfactant cetyltrymethyl ammonium bromide (CTAB) with ammonium nitrate (NH4NO3) salt. Surface and thermodynamic properties of cationic surfactant CTAB with ammonium nitrate salt were investigated at different temperatures through different techniques like conductometry and surface tensiometery. The surface tension measurement was carried out to find out the critical micelle concentration (CMC), free energy of adsorption (?Gads), free energy of micellization (?Gm), minimum area per molecule (A) and surface excess concentration (Г). The study reveals that the process of micellization is spontaneous and exothermic in nature. Conductance measurement enabled us to determine CMC, degree of ionization (α), degree of counter ion binding (β). Upon addition of NH4NO3 to the surfactant solutions increase the values of α and β, although it lowers the values of CMC showing that the process of micellization is more favorable and spontaneous. The study is very helpful to develop better understanding about interaction between electrolyte and surfactant.