The Commission of the (Catholic) Bishops’ Conferences of the European Community (COMECE) has issued an opinion on the ethics of synthetic biology (synbio). Examining synbio from religious and more general ethical perspectives, it examines synbio’s potential pros and cons, as well as whether it is ethical in and of itself. Its conclusions mirror those of the ethical mainstream; namely, that synbio may present humanity with opportunities for both great advancement and great destruction. It suggests a prudent approach, and calls for regulation to be used to encourage positive outcomes while reducing the likelihood of negative ones.