A programme for monitoring the impact of organic waste from marine fish farms is presented. It consists of three types of investigation of increasing complexity and accuracy (A, B and C), which are applied more frequently with increasing environmental impact. The A-investigation is a simple measurement of sedimentation rate beneath the net cages; the B-investigation is a sediment investigation providing a trend monitoring of the sediment condition, and the C-investigation is a comprehensive investigation of the benthic macrofaunal community structure. The A- and B-investigations were designed specifically for fish farming and the latter utilises several parameters in order to make the investigation more robust. The C-investigation employs well-established methods and procedures, which have been used previously in monitoring programmes. Environmental quality standards (EQS) have been set for the B- and C-investigation. The monitoring programme is part of a larger management system in Norway called Modelling-Ongrowing fish farms-Monitoring (MOM).