In a programme started in 1988, the waste water discharges from the major chemical industries in Sweden have been investigated. The primary objectives were to gather information on the major sources of such discharges and to initiate action so as to achieve significant reductions where required. In this paper the investigation programme is presented together with some early conclusions. As could be expected there are no simple common rules for these industries, each effluent should be considered as a separate problem. It was concluded that these waste waters were in most cases more toxic than was acceptable, and that further purifying measures were required in these cases.