Cardanol obtained from decraboxylated cashew nut shell liquid was used for preparation of sodium cardanol sulfonate surfactant, by sulfonation of cardanol with fuming sulfuric acid at temperature of 10 ℃ for 2 hours and room temperature for 3 hours, and then by neutralization with sodium hydroxide at room temperature for 1 hour. Surfactant properties of cardanol sulfonate were determined and compared with dodecylbenzene sulfonate. Surface tension values were measured to be 32.3 mN/m for cardanol sulfonate at 20 % w/v and 28 mN/m for dodecylbenzene sulfonate at 15 % w/v. Critical micelle concentrations of 0.435 and 0.372 mol/l for dodecylbenzene sulfonate and cardanol sulfonate, respectively, were found. Using dodecylbenzene sulfonate as reference, the relative detergency of 93.7 % for cardanol sulfonate was obtained. Results suggest that cardanol sulfonate can be used as anionic surfactant.