We have assessed the macrophage response to polypropylene mesh (Marlex) implanted into the abdominal wall of New Zealand white rabbits, using RAM-11, a monoclonal antibody specific for rabbit macrophages. The response diminishes during the course of the first 90 days after implantation, although the presence of other cell types typical of foreign-body reactions increases. We have also confirmed the high degree of integration of the biomaterial into the wall achieved after 9 weeks. This has been determined using light and scanning electron microscopy. Likewise, we have observed the formation of numerous adhesions between the polypropylene mesh and the viscera of the abdominal cavity.