In the past ten years, many European companies organised into subcontracting networks have decided to adopt codes of conduct to regulate labour relations and to ensure the respect of fundamental social rights. This paper first determines the context and the issues to be addressed by codes of conduct within networks of companies, and second analyses the terms under which they can be implemented. The paper argues that codes of conduct can complement the standards developed by States, the European Union or (...) the social partners, but that steps should be taken in order to avoid that these texts replace the existing labour law. (shrink)