Abstract The comitology regime, the committee-based system developed as a mechanism for controlling the Commission's exercise of its powers to implement EU measures, has been subject to severe criticism on grounds of lack of accountability and transparency. The system has recently been fundamentally reformed by means of the new Implementing Acts Regulation, which came into force on 1 March 2011. This paper investigates whether the new rules are sufficient to remedy accountability deficits as regards implementing acts and concludes that as far as accountability to the Member States is concerned, their control powers have remained static. In addition, the new-delegated acts procedure introduced by the Treaty of Lisbon grants the European Parliament (EP) more control powers, although the EP's gains are more modest than they might appear. This change has come at the cost of reduced control powers for Member States as well as lowered standards of transparency for the public.