Been joined his boyhood club Feyenoord in the summer of 2009 in the hope of repairing the financially stricken club.
He was given a very youthful squad to work with, which did have some experienced heads in the form of Roy Makaay, Denny Landzaat and Giovanni van Bronckhorst.
His first signing was from his old club where he signed Dani Fernández for the right-back position.
Been's first season for Feyenoord was immediately a success as he led them to a fourth-place finish in the league and thus a place in the Europa League for the 2010–11 season.
This was also the club's highest finish for a few years.
In a turbulent summer which saw all his experienced heads retire, he signed only a handful of players on free transfers or by loan.
Feyenoord started the campaign in mixed form.
On the opening day they beat FC Utrecht 3–1 to kick off a good start to the campaign.
However the club failed to qualify for the group stages of the Europa League after they lost 2–1 to AA Gent on aggregate.

Up until 2011, Been has a contract until 2012 with the club.
On 24 October 2010, he oversaw his team losing 10–0 against PSV Eindhoven at the Philips Stadion the biggest defeat in the history of Feyenoord.
Despite that, and a rather disappointing final outcome that saw Feyenoord failing to qualify for European football and even in danger of relegation at some point in the season, he was confirmed at the helm of Feyenoord for the new season.

On 13 July 2011, Been was confirmed to have left his post as head coach of Feyenoord, citing lack of trust and confidence from his players as the main reason for his surprise choice.
Been joined his boyhood club Feyenoord in the summer of 2009 in the hope of repairing the financially stricken club. He was given a very youthful squad to work with, which did have some experienced heads in the form of Roy Makaay, Denny Landzaat and Giovanni van Bronckhorst. His first signing was from his old club where he signed Dani Fernández for the right-back position. Been's first season for Feyenoord was immediately a success as he led them to a fourth-place finish in the league and thus a place in the Europa League for the 2010–11 season. This was also the club's highest finish for a few years. In a turbulent summer which saw all his experienced heads retire, he signed only a handful of players on free transfers or by loan. Feyenoord started the campaign in mixed form. On the opening day they beat FC Utrecht 3–1 to kick off a good start to the campaign. However the club failed to qualify for the group stages of the Europa League after they lost 2–1 to AA Gent on aggregate.
Up until 2011, Been has a contract until 2012 with the club. On 24 October 2010, he oversaw his team losing 10–0 against PSV Eindhoven at the Philips Stadion the biggest defeat in the history of Feyenoord. Despite that, and a rather disappointing final outcome that saw Feyenoord failing to qualify for European football and even in danger of relegation at some point in the season, he was confirmed at the helm of Feyenoord for the new season.
On 13 July 2011, Been was confirmed to have left his post as head coach of Feyenoord, citing lack of trust and confidence from his players as the main reason for his surprise choice.
Mario Been