Due to the multitude of phases that may be deposited as a result of varying degrees of target poisoning, the vanadium oxygen system provides a vehicle for studying the reactive sputtering process. Examination of the consumed O-2 partial pressure, target voltage, deposition rate, and change in film composition as a function of the oxygen partial pressure, shows how the target is poisoned by oxygen, The sputtering yield for V as a function of O-2 partial pressure was measured by a novel technique that collects a known fraction of the sputtered flux. The V sputtering yields were used to help determine the O sputtering yield by an analytical model based upon the work of Berg et al. Target sputter cleaning in pure Ar and the oxidation of a partially oxidized metal surface exposed to an O-2 ambient an shown to approach completion following an exponential time dependence. The target and substrate oxidation are shown to be well simulated by a modified version of existing reactive sputtering models and give reasonable values for the sputtering yield of oxygen from the target surface.