Article 94 EC and – of primary significance today – Article 95 EC envisage legislative intervention by the EC to harmonise national laws as a means to improve the functioning of the market. In some areas diverse national rules affecting private law have been subjected to the discipline of legislative harmonisation, with the consequence that the EC has assumed the responsibility to shape private law. The European Court, which unavoidably becomes involved in the interpretation of phrases and concepts contained in these measures, is accordingly transformed into a court with a role to play in developing private law. Beneath this basically accurate yet deceptively simple explanation lurk a clutch of awkward questions. Among them: To what extent are there discernible principles which provide thematic binding to the legislative acquis? What is the scope of the Court’s role in imprinting a distinct vision on the material it is asked to interpret? This paper will touch on these questions, but its principal focus is on the European Court’s readiness to extract and develop general principles of private law from litigation arising under or near to the legislative acquis. Its track record will be shown to be intriguingly mixed, ranging from cautious interpretation of detailed provisions that resists transplant to a more general level to remarkably ambitious willingness to find solutions that are by no means evidently mandated by the explicit terms of relevant EC measures. The Court’s case law, then, is an unavoidable but inconsistent source of EC private law.