Potentiodynamic polarization experiments were performed in 0.1N hydrochloric acid and in 1N sodium chloride with austenitic alloys containing 18 to 20% Cr, 13 to 39% Ni, 0 to 5% Mo, and balance Fe. The pitting potentials varied consistently with alloy content and correlated well with the results of exposure tests in 0.33M ferric chloride. Increasing the molybdenum and nickel contents increased the resistance to pitting; however, decreasing the carbon and nitrogen contents also increased the resistance to pitting. Critical current densities for passivity decreased sharply at all nickel levels with increases in the molybdenum content.