Using an integrated approach, the genotoxic potential of bis(tri‐n‐butyltin), an antifouling agent known to disrupt endocrine system in marine invertebrates, has been evaluated in the embryo‐larval stages of the edible mussel, Mytilus edulis. While evaluating the genotoxic potential, the toxicity of tributyltin was also taken into account by determining the maximum tolerated dose. The study suggested that tributyltin is capable of inducing cytogenetic damage (sister chromatid exchanges and chromosomal aberrations) in this target species. The study emphasises the need for further investigations of the potential genotoxic effects of this and other endocrine disrupters on ecologically relevant aquatic invertebrates, which contribute to the maintenance of ecosystems and that could potentially be harmful to human health via the food chain. Environ. Mol. Mutagen. 35:343–350, 2000 © 2000 Wiley‐Liss, Inc.