A series of surface active sulfo‐propane betaines and sulfo‐butane betaines were synthesized with high yields by the reaction of an appropriate N,N‐dimethyl alkylamine with an excess of 1,3‐propane sultone and 1,4‐butane sultone. The structures were characterized by 1H‐NMR spectroscopy and elemental analysis. The micellar properties of these compounds were determined by surface tension methods. Surface