The introduction indicates the legal position relative to the control of discharges to the Forth estuary. Details are given of the volumes of the known sources of pollution, in 1958; chemical, bacteriological and biological data then follow relative to a survey carried out in August and September of that year. The conclusions, drawn from the 1958 Survey, emphasised the gross pollution existing at that time, and suggested methods whereby the pollution might be reduced. Section 4 of the paper discusses the results of chemical, biological, bacteriological and hydrographical surveys carried out since 1962. The results stress the deterioration in conditions in the estuary compared with the earlier survey, and in particular, the lower dissolved oxygen concentration in inshore waters and the increase in the Coliform and Escherichia coli counts in certain areas. Isolation of Salmonella species implies the possible health hazards existing at the present time. Work so far carried out in respect of the determination of heavy metal concentrations in core samples taken in the intertidal zone along the shore has indicated relatively high concentrations of certain metals and their effect on the ecology of the estuary has yet to be fully assessed. Float tests made over a period emphasise the tendency for the sewage discharges to be confined to inshore waters, resulting in the gross pollution of certain beaches. Present information stresses the need for the continuance of the monitoring programme.