A set of wind-tunnel data is presented which describes the concentration distributions resulting from diffusion of a passive tracer in the near-wake of a cubical building. Sources were located near ground level both upstream and downstream of the building, and centered atop the building. Ground-level centerline concentrations predicted by several simple models for dispersion in building wakes were compared with the measured wind-tunnel data in order to determine the limits within which such models could be expected to provide acceptable predictions. The Huber-Snyder model was found to provide very good agreement with the ground-level centerline concentrations, but at the expense of underpredicting the lateral plume spread. The Ferrara-Cagnetti model provided better agreement with observed plume spreads, but underpredicted the observed concentrations. Based upon observations of transport speed in the wake of similar obstacles, a simple modification to the Ferrara-Cagnetti model is suggested which improves the prediction of concentrations while still providing reasonable estimates of the plume spread. The application of various types of building-wake diffusion models is briefly summarized.