Abstract This paper describes the use of field data on drilling mud and produced water dispersion to verify the Offshore Operators Committee (OOC) Mud and Produced Water Discharge Model (the “OOC Model”). Field studies for produced water and water-based drilling mud discharges provided data on effluent properties, discharge rates and pipe diameters, ocean currents, water column salinity and temperature, and measured effluent concentration at distances up to 103 m downcurrent from the discharge point. Data on effluent properties and field conditions were used as input data for OOC Model predictions of water column concentrations. This paper compares concentrations predicted by the OOC Model with field observations and describes the field data in sufficient detail to support their use to check the performance of other related models. The measured concentrations exhibited high variability due to turbulence and ambient current variations. The field data nonetheless showed clear trends in dilution with distance from the discharge point and demonstrated that both produced water and drilling mud discharges are rapidly diluted after discharge into the marine environment. There was good agreement between field observations and OOC model predictions. The results of these studies document the ability of the OOC Model to predict concentrations from field discharges of drilling mud and produced water.