The manual presents a two-dimensional computer model, BIOPLUME II, that simulates the transport of dissolved hydrocarbons under the influence of oxygen-limited biodegradation. BIOPLUME II also simulates reaeration and anaerobic biodegradation as a first order decay in hydrocarbon concentrations. The model is based on the USGS solute transport two-dimensional code (Konikow and Bredehoeft, 1978). The model computes the changes in concentration over time due to convection, dispersion, mixing, and biodegradation. The same numerical techniques that are used in the USGS code are maintained in BIOPLUME II. BIOPLUME II solves the solute transport equation twice: once for hydrocarbon and once for oxygen. As a result, two plumes are computed at every time step. The model assumes an instantaneous reaction between oxygen and hydrocarbon to simulate biodegradation processes. The model is extremely versatile in that it can be used to simulate natural biodegradation processes, retarded plumes, and in-situ biorestoration schemes. BIOPLUME II allows injection wells to be specified as oxygen sources into a contaminated aquifer. This means that alternate methods for aquifer reclamation can be investigated to design the most economically feasible scheme.