Four azobenzene amphiphiles containing tertiary amide groups were synthesized and characterized. Reversible cis/trans photoisomerization of these compounds has been studied in solutions by irradiation with UV light at 335 nm and visible light at 452 nm. Stability of the monomolecular layer, the collapse pressure, and the molecular area have been investigated as a function of chemical structure of azobenzene derivative and of equilibrium concentration of the cis and trans form in spreading solution.