At the national level there are three institutions, with supervisory and controlling powers, with which the Authority cooperates on a regular basis: the Bank of Italy, the Istituto per la Vigilanza sulle Assicurazioni Private e d'Interesse Collettivo (ISVAP, the regulatory body which supervises insurance companies) and the Autorità per le garanzie nelle comunicazioni (the Italian regulator for communications).

The Investment Protection Act (Law no. 262 of 28 December 2005) repealed Section 20(2), (3) and (6) of Law no. 287/90 which required the Bank of Italy to enforce competition law in relation to agreements, abuses of dominant position and mergers and acquisitions involving banks, and governed relations with the Authority. The new provisions give the Authority full and exclusive powers in relation to agreements and abuses of dominant position in the banking sector and, with regard to acquisitions and mergers, powers to assess competition, while the assessment in terms of prudent and sound management falls under the powers of the Bank of Italy.

The Authority is required to request the Italian regulator for communications a non-binding opinion on the draft of the decisions related to agreements between undertakings, abuses of dominant position and mergers and acquisitions, when the communications market is concerned. Viceversa, the regulator is required to request the Authority a non-binding opinion on a number of matters (e.g., with reference to the definition of the operators with a significant market power, the interconnection offer, etc.).

In cases of misleading and comparative advertising, it is the Authority itself that must request a non-binding opinion from the Italian regulator for communications in the case of advertisements via radio or television.

In the insurance field, the Antitrust Authority is responsible for the enforcement of the Act, but it is required to request the non-binding opinion of ISVAP.

The Antitrust Authority maintains relations with other regulatory bodies, and with the Autorità per l'energia elettrica e il gas (the Italian regulator for electricity and gas) in particular.