The behavior of copper in borate buffer solution (pH 7) in the presence of the surfactant dodecylsulfate was studied using cyclic polarization, the electrochemical quartz crystal microbalance technique, and scanning electron microscopy. The results indicate absorption of dodecylsulfate causing severe pitting of the copper surface. The pitting potential (E-p) in the presence of 1000 ppm (3.5 x 10(-3) M) surfactant is 0.04 V (vs. a standard calomel electrode) and it varies with the dodecylsulfate ion (DS-) concentration: E-p (V) = -0.123 log[DS-] -0.268. It is postulated that the formation of the complex Cu(DS)(2) is involved in the pitting mechanism.