Faull's responsibilities will be split in the wake of his departure, with deputy Reijo Kemppinen stepping up to the top spokesman role.
The other side of Faull's remit - as director-general of the press and communications directorate - will be filled by an internal recruitment process that Kemppinen said could last 'around a couple of months'.
Faull, who moves to become head of the justice and home affairs directorate on 15 March, had headed the press and comms directorate since November 1999.
He assumed added responsibility as spokesman for the commission, and its president, in around April 2000.
From autumn 2000 to the start of last year, Kemppinen was deputy spokesman to commissioner for external relations Chris Patten.
Overall, the EC's press and comms directorate employs around 700 staff across the 15 member states. It aims to communicate the Commission's activities and policies to EU member states' citizens.
Kemppinen said a major comms issue on the horizon surrounded planned constitutional change in advance of the admission of new members to the European Union.
In June next year the European Council will meet to elect a commission - and president - to replace Prodi, who will retain his role until the end of 2004. Kemppinen said his contract would last until then.