Repair of a groin hernia is strongly influenced by prosthetic mesh implantation carried out in nearly 50 % of all operations. Recurrency rates, however, did not decrease by this policy. Many different materials are available. Due to bioinstability on the long-term and elevated infection rates PTFE is not suitable for inguinal hernia repair. Polyester also provides no long-term stability and induces a chronic foreign body reaction. Polypropylene initially leads to an acute inflammatory reaction and often ends in fibrosis. Both reactions are related to the weight of the used mesh. All materials may lead to specific complications. These include seroma formation, infection, migration of the prosthesis with arrosion of organs, damage of the vas deferens, development of recurrency by shrinkage of the fibers around the mesh, formation of adhesions in the preperitoneal position, and chronic inguinal pain. Therefore, meshes should be used only after individual estimation of risks and benefit. This includes the hernia classification, the number of previous operations and the possibility of a defect in collagen metabolism. The unknown long-term risks for the patient may be taken only in strong indications.