The most likely entry pathways of veterinary medicinal products (VMPs) into the environment are via slurry or manure from intensively reared animals to soil, and via dung or urine from animals grazing on pasture. Surface water may be contaminated via run-off or leaching and drainage, or by direct excretion of pasture animals into water. According to EU legislation, each new application for authorisation of a VMP has to include an environmental risk assessment. However, for many old VMPs, consistent data on possible environmental risks have not been generated. In this project, a simple procedure was developed to assess the environmental hazard potential of veterinary medicinal products. Information on the typical treatment scenarios was collated for 233 active substances. A risk-based ranking approach was performed in four phases: (1) usage estimation, (2) exposure characterisation based on application scenario, (3) effects characterisation based on therapeutic dose, and (4) risk characterisation, which is the ratio of exposure to effects (risk index), and ranking. Generally, the top ranked substances were antibiotics and antiparasitics. The developed ranking scheme is a scientifically-based and pragmatic means of assessing the relative priority of veterinary medicines for further detailed risk assessment. The individual rank of a substance might facilitate case-by-case decisions to be taken on the re-evaluation of the risk-benefit balance for renewals.