The critical micellar concentrations of pentacainium chloride in methanol and ethanol solutions with different concentrations were determined by the spectrophotometric method in the UV region of the spectrum at the temperature range of T = 278.15-308.15 K and pH = 4.5-5.0. The dependence of cmc on temperature T turned out to be U-shaped. The influence of the n-alkanols, methanol and ethanol, on the critical micellar concentration was studied. The cmc values show that micelle formation occurred more easily in methanol than in ethanol solutions. Simultaneously the influence of various concentrations of alcohols was studied. The critical micellar concentration rises with an increasing concentration of alcohol up to some value, then cmc decreases.