Surface properties of two amphiphilic drugs i.e. amitriptyline and imipramine have been studied in the absence and presence of some cationic surfactants i.e. alkyltriphenylphosphonium bromide [R = 16 (CTPB), R = 14 (TTPB)] and alkyldiethylcthanolammonium bromide [R = 16 (CDEEAB), R = 14 (TDEEAB)] by surface tension measurement at 300 K. The critical micelle concentration (CMC), maximum surface excess concentration at the air/water interface (Γmax), minimum area per surfactant molecule at the air-water interface (Amin) and the surface pressure at the CMC (πCMC) have been determined. Γmax value increases and CMC/πCMC decrease & with an increasing mole fraction of surfactants. The solubility of amphiphilic drugs in cationic surfactant systems has also been studied.