Mariano Rubén Puerta (Spanish pronunciation: [maˈɾjano ruˈβem ˈpweɾta];[a] born 19 September 1978) is an Argentine tennis coach and former professional player.

In 2005, Puerta made an eye-opening comeback on the Tour by winning the title in Casablanca and then making it to the final of the world's most prestigious clay court tournament, the French Open, where he eventually succumbed to Rafael Nadal in a close match (7–6(8–6), 3–6, 1–6, 5–7).

On June 6, 2007, Puerta returned to the professional circuit with a 6–4, 6–3 victory over Australian Joseph Sirianni at the Sassuolo Challenger, a tournament to which he was invited as a wild card since he had no ranking.

In December 2005, Puerta was banned again, this time after it was revealed that he had tested positive for the use of the cardiac stimulant etilefrine following his 2005 French Open final loss to Rafael Nadal.

The International Tennis Federation tribunal noted, however, that "The amount of etilefrine detected in the positive drugs test was too small to have any effect on his performance".

[3] Puerta appealed against the ban, claiming on his web site that he only ingested trace amounts of it accidentally left over by his wife in a glass.

On July 12, 2006, his suspension was reduced to two years by the Court of Arbitration for Sport, making him eligible to restart his career on June 5, 2007.