A customizable in silico tool (SusTool) for generating high resolution mass spectrometry (HRMS) suspect screening lists, specifically designed for the detection of hazardous organic compounds in various environmental compartments, was created. A database consisting of similar to 32 000 environmentally relevant organic compounds was constructed, including data on their physicochemical properties, environmental fate characteristics, and endocrine disruption potential, along with emissions and quantity indices. Welldefined customized suspect lists were generated by systematic ranking using a scoring and weighting procedure. For demonstration purposes, three suspect screening lists were created, one for water (SLWater) and two for biota covering less (SLBiota Kow<5 ) or more hydrophobic chemicals (SLBiota Kow>3). Scrutiny of overlaps between compounds within these lists and the SusDat database (20 suspect lists comprising similar to 58 000 compounds compiled by the Norman network) showed that approximately half of the compounds in the three suspect lists were also listed in one of the SusDat database lists. This indicates that SusTool is able to include highly relevant emerging pollutants, but also captures other compounds of potential concern that have been less well studied or not yet investigated. Overall, our in silico prioritization approach enables systematic creation of suspect screening lists and provides new opportunities for suspect screening for environmentally relevant compounds.