ABSTRACT Bioremediation of oil-contaminated shorelines can be effected by providing sufficient quantities of certain rate-limiting nutrients, especially nitrogen and phosphorus. Although stoichiometry, based on the determination of optimal C:N:P ratios from batch oil-biodegradation experiments, traditionally has been the primary method for estimating required nutrient dosages, recent research suggests that nutrient uptake and microbial growth kinetics may be more important in determining the success of oil spill bioremediation. Because nutrient washout can be relatively rapid in intertidal environments, nutrient application strategies must consider the relative rates of nutrient washout and uptake by microorganisms. Because there may be significant differences between ammonium and nitrate with respect to both of these processes, a laboratory investigation of the performance of these two nitrogen sources was conducted in continuous-flow beach microcosm reactors. The behavior of these nutrients was compared under abiotic conditions to determine whether ammonium could be retained in oil-contaminated beaches longer than nitrate by ion exchange. Their ability to support oil biodegradation under continuous and intermittent feeding conditions also was compared. No differences between ammonium and nitrate could be detected based on either criterion, but faster oil biodegradation was observed under pulse-feeding conditions than when the nutrients were supplied continuously. The relatively poor performance of the continuously fed systems was attributed to nutrient limitation because the nutrient input rate was less than the nutrient demand rate.