He entered the St. Petersburg tournament in October 2003 as a wildcard, and defeated fourth seed Max Mirnyi 6–4, 7–6 before losing to Sargis Sargsian in the second round.

He won his first ATP doubles title in Moscow in October 2004 with Nikolay Davydenko, defeating Mahesh Bhupathi and Jonas Björkman 3–6, 6–3, 6–4 in the final.

Andreev's first ATP singles title came in April 2005 in Valencia, Spain, beating Spaniard David Ferrer 6–3, 5–7, 6–3 in the final after having taken out Rafael Nadal in the quarterfinals.

Andreev made the third round at both the French Open and Wimbledon, and reached the quarterfinal at the Pilot Pen Tennis Tournament in New Haven, Connecticut.

In the first half of the season, Andreev experienced seven first-round losses, and highlights included reaching the finals at Sydney and the quarterfinals at Indian Wells, losing both matches to James Blake.

A knee injury forced Andreev to miss the second half of the clay court season, including Roland Garross.

Heavily favored Russia was hosted by Israel in a Davis Cup quarterfinal tie in July 2009 on indoor hard courts at the Nokia Arena in Tel Aviv.

His next successful tournament was the Malaysia Open where he reached the semifinals, taking out defending champion Nikolay Davydenko on the way before falling to Mikhail Youzhny in three sets.

At Wimbledon 2013 Andreev appeared in the main draw as a protected ranking player and in the first round he faced Polish Łukasz Kubot losing 6–1, 7–5, 6–2.