The applicable law to a contract in the absence of the parties' choice is governed by Article 4 of the Rome Convention, which has been implemented in the UK by the Contracts (Applicable Law) Act 1990. This rule adopts the ‘closest connection principle’ as a basic principle to decide the applicable law, but also introduces specific presumptions to simplify the process. The current rule has been criticised for its uncertainty. As a result, a substantive change has been provided in the Rome I Regulation, which aims to modernise the current choice of law rules in contractual obligations and convert the Rome Convention into a Council Regulation. The new Article 4 aims to enhance certainty and to overcome the difficulties of the current rules of the Rome Convention. However, a close scrutiny of the new Article 4 shows that it does not properly achieve its aim. The article aims to critically analyse Article 4 of the Rome I Regulation and to provide suggestions for its interpretation and understanding.