Although Chile is an important world supplier of marine products, several processing factories have not applied clean technology to improve productivity and reduce the environmental impact of dumping their effluents to coastal seawater. To achieve these goals they need to evaluate their processes and management of effluents. A case-study of a factory independently processing crustacea, jack mackerel, salmon and Ðshmeal was carried out. It was found that this type of factory could diminish effluents by saving an average 31É8% in water consumption. Segregation of streams by organic load and Ñow allowed salvaging of reusable organic matter from the most loaded streams and the design of a combined anaerobicÈaerobic treatment for effluents. Final effluents complied with future legal regulations (0É15 kg COD m~3 and 0É05 kg total nitrogen m~3) for their disposal in marine outfalls. Estimated installation costs for the equipment required for organic matter recovery and effluent treatment (primary and secondary) were US$ 37.3 per tonne of product. Recovered organic matter incorporated to the Ðshmeal process can provide an extra 5É5 tonnes day~1 of the product, which represents savings of at least US$ 308 000 per year which could partly pay for the secondary treatment cost of the effluents. 1998