Abstract The kinetics of dissolution of lead, thallium and zinc amalgams in contact with acid solutions containing dissolved oxygen were studied. The results were interpreted on the basis of the Wagner theory of the additivity of electrochemical part-processes. It was found that the rate of dissolution may be described by the differential equation for zero-order reactions. The numerical values of the rate constants of the dissolution were determined and compared with the values calculated on the basis of the limiting diffusion current of the oxygen reduction. The results confirm that the diffusion of the oxygen depolarizer is the rate-determining part-process.