The influence of a high N-2 background pressure on the molecular beam epitaxy growth of GaAs has been investigated. Measurements to determine the minimum As-4 pressure necessary to maintain stoichiometric growth at different substrate temperatures with and without a high N-2 background pressure were performed. The As-4 pressures required for cases when a high N-2 background was present were systematically above those required without a N-2 background. The GaAs growth process has been modeled using kinetic rate equations and by including surface site blocking terms the model accounts for the data taken by the authors. The model also agrees well with GaAs growth kinetic data published by several other authors. (C) 2004 American Vacuum Society.