Experimental evidence is herein given of lower critical solution temperatures in high salt aqueous solutions of cetylpyridinium and cetyltrimethylammonium bromide, nitrate and chlorate. The critical behaviour of the solutions is followed using static and dynamic light scattering. The unique feature of this transition lies in the unusually large values of the correlation length ξ (> 103 A) more than 10 °C below the critical temperature. The occurrence of the phase separation seems to be connected with the existence of giant rod-like flexible micelles in the solutions. The analogies with critical solutions of polymers are underlined.