Using data from Uruk sites in southwest Iran, this study examines the effects of depositional context and social variables on the composition of faunal assemblages. Examination of samples from inside structures and open midden or trash pits showed that delicate bones belonging to small or young individuals were more likely to survive inside buildings, and larger bones to be deposited outside. Comparison of Early, Middle, and Late Uruk samples shows an increase in the presence of sheep/goat and pig, but indicates that utilization of cattle remained constant. Little social variability was indicated by comparison of samples associated with high status and low status buildings, or from areas associated with administrative and non-administrative activities.