Interactions among local pit sites were investigated using an array of 25 electrodes. The 5 x 5 array consisted of closely spaced, flush-mounted 316 stainless steel wires polarized in 0.05 M NaCl solution. Two types of interactions occurred when either single or rows of actively corroding pits existed while the remaining electrodes were initially passive. Inhibition of pitting on nearby electrodes occurred due to ohmic potential drop near active pre-existing pits. Enhancement of pitting was observed due to alterations in the local solution composition near just deactivated pits. The former effect was stronger than the latter, but the concentration effect could persist after pit deactivation.