The kinetics of manganese binding and oxidation by a marinePseudomonassp. have been determined under nutrient‐limited, steady‐state conditions. The first‐order rate constants for manganese binding by steady‐state cultures increased logarithmically with growth rate and were well within the range of values published for a variety of sedimentary and aquatic environments. In addition, the rate of manganese binding per cell appeared to be far faster than the growth kinetics.