Ferrero made his ATP main draw debut at the Grand Prix Hassan II as a qualifier, where he reached the semi-finals.

Ferrero then helped his Davis Cup team get back to the World Group stage by defeating Uzbekistan's Oleg Ogorodov.

In the round robin stage, he lost to Yevgeny Kafelnikov, but defeated Gustavo Kuerten and Goran Ivanišević to advance to the semifinals.

Ferrero represented Spain in its Davis Cup tie against Morocco, where he won against Hicham Arazi but lost to Younes El Aynaoui.

In the round robin stage, Ferrero recorded a loss against Roger Federer but wins over Andre Agassi and Jiří Novák to advance to the semifinals.

Ferrero once again represented Spain at Davis Cup in a tie against Belgium, where he won both of his matches, defeating Christophe Rochus and Kristof Vliegen.

At the Tennis Masters Cup, he lost all three of his round robin matches against David Nalbandian, Andre Agassi, and Roger Federer.

He reached his second final of the year at the Vienna Open, defeating David Nalbandian and Radek Štěpánek en route before losing to Ivan Ljubičić.

[18] Ferrero ended the year on a five-match losing streak, beginning with a loss in the second round of the US Open to Marc Gicquel in straight sets.

Ferrero then suffered three consecutive losses: to Nicolas Mahut at the second round of the Open 13, in Rotterdam to Teymuraz Gabashvili, and in Dubai to Andy Roddick.

Ferrero then played the French Open, where he won the first set of his first round match against Marcos Daniel before retiring due to a leg injury.

However, he then reached the quarterfinals of the Brasil Open, where he lost to Thomaz Bellucci, and of Buenos Aires, where he retired against David Nalbandian with a leg injury.

In March, Ferrero captured his first singles title since 2003 by defeating fifth–seeded Serra in the final of the Grand Prix Hassan II in Casablanca, Morocco.

[25] At Buenos Aires, Ferrero defeated top seed David Ferrer in the final to take his second title in a row and extend his winning streak to ten matches.

At the Mexican Open in Acapulco, Ferrero defeated Diego Junqueira, Igor Andreev, defending champion Nicolás Almagro and Juan Mónaco to reach his third consecutive final.

Ferrero defeated Daniel Köllerer in the second round of Indian Wells to claim his first hard-court victory of the season, losing only eight points on serve.

At the Monte Carlo Masters, he defeated Marcel Granollers, Benjamin Becker and Tsonga before losing to Rafael Nadal in straight sets in the quarterfinals.

Ferrero then won his third title of the year at the Umag Open, beating Pablo Cuevas, Alexandr Dolgopolov, Andreas Seppi, and Potito Starace in the final.

He also withdrew from Mexico, Indian Wells, Miami, and Monte Carlo, as the recovery from his wrist and knee surgery took longer than expected.

Ferrero made his return at the Barcelona Open, where he defeated Xavier Malisse, Mischa Zverev, and Simone Vagnozzi, but lost in the quarterfinals to Nicolás Almagro.

There, he defeated Bastian Knittel, Mikhail Youzhny, Marcel Granollers, Federico Delbonis, and straight-setted Pablo Andújar in the final to capture the title.

[29] Ferrero represented Spain in the Davis Cup for the last time in a tie against Kazakhstan, where he defeated Mikhail Kukushkin in five sets.

He beat Robin Haase after saving a match point, but lost to Brazilian qualifier Thomaz Bellucci in the second round in straight sets.

"[31] Ferrero played his final singles match in the first round of the Valencia Open, where he lost to fellow Spaniard Nicolás Almagro in straight sets.

[32] In 2017 it was announced that Ferrero would return to the ATP Tour to play in the Barcelona doubles draw alongside Pablo Carreño Busta.

He made his Davis Cup debut for Spain in a quarterfinals match-up against Russia in 2000, where he won both his matches, against Yevgeny Kafelnikov and Marat Safin, in straight sets.

Ferrero made up for this loss, however, when Spain competed in the qualifying rounds for the Davis Cup World Group, where he defeated Oleg Ogorodov of Uzbekistan in straight sets.

In 2004, Ferrero won both of his singles matches in Spain's quarterfinal against the Netherlands, defeating Sluiter in straight sets and Martin Verkerk in five.

However, Ferrero was unceremoniously dropped from Spain's line-up the day before the finals against the United States began, in favour of Rafael Nadal.

After the tournament, Nadal denied rampant media speculation that there was bad blood between him and Ferrero: "You have to understand Juan Carlos' situation.