Danish fish processing industry has been one of the pioneers regarding implementation of cleaner production and environmental management systems. This article describes the experiences with cleaner production (CP) among leading Danish industries producing pickled herring and canned mackerel. The article emphasizes two case studies of ‘first mover’ companies, but data from other ‘proactive’ companies are also included. The article provides an overview of different types of CP solutions, improvement potentials, synergistic effects and possible trade-offs. The development of the applied solutions from the late 1980s until today are analysed and recommendations to future strategies at company level and policy level are provided. It is concluded that significant environmental improvements have been obtained for the analysed companies – especially concerning reductions in water consumption, wastewater emissions, and utilisation of fish ‘waste’ for valuable by-products. Still, more focus could be placed on the reduction of energy consumption, change of packaging types, and environmental impacts in other stages of the products life cycle. Authorities and companies have mainly focused on on-site reductions of wastewater emissions, but life cycle assessments show that more attention should be given to the reductions of environmental impacts in other parts of the product chain, e.g. fishing operations and transport as well.