Pesticides originating from agricultural land are considered one of the three key contaminants reducing the quality of water entering the Great Barrier Reef lagoon, with the sugar cane industry identified as a significant contributor. To date, efforts have focused on reducing pesticide runoff by improving farm management. A complementary approach is to provide farmers with information so they can select and use pesticides that pose a lower risk to aquatic plants and animals. The Pesticide Decision Support Tool (PDST) aims to provide such guidance to farmers, re-sellers, extension officers and agronomists. The PDST currently includes 47 pesticide active ingredients, including all of the organic pesticide active ingredients registered for use on sugar cane, as well as some active ingredients used on rotation crops. The PDST uses the relative measure of effect and relative mobility and persistence of active ingredients to determine the aquatic risk. Relative measure of effect indicates the potential toxicity of the active ingredient using Australian and New Zealand water quality guidelines or their equivalent and indicates the potential of active ingredients to exert hazardous effects on aquatic organisms. The relative mobility and persistence indicates the potential of active ingredients to move from farms to waterways and to persist in water. Available in both poster and interactive spreadsheet forms, the PDST can help farmers select pesticide active ingredients with a lower aquatic risk. The PDST is currently being expanded, with approximately another 58 active ingredients being added. The user training will begin shortly and the success of the PDST in reducing the use of high aquatic risk pesticides will be assessed over time.