Ataman began his managerial career in Eczacıbaşı Youth Team. Secondly, he was dutied in Efes Pilsen Youth Team. Then, he coached the BSL teams Türk Telekom, Pınar Karşıyaka and Efes Pilsen respectively. He was the assistant coach of Turkish national team alongside Ercüment Sunter in EuroBasket 1997 in Spain. Turkey had the 8th place in that tournament. He had spent some time at Stanford University in the United States for making observations about basketball whilst 1998-99 season. After his return to Europe, he coached Italian side Montepaschi Siena and achieved the very last Saporta Cup in 2002. Subsequently, he joined Ülkerspor ; however, he had to quit his job due to his private life to be highlighted by the press. On his declaration, he stated that resigned for the favours of the club. At the same season, he went again to Italy and work there. He signed for Climamio Bologna and coached this time until he dealt with Beşiktaş in the opening phase of 2007–08 season.
Ataman had a successful season with Beşiktaş which the team achieved EuroCup Quarter Finals held in Turin, Italy; after a stunning undefeated 10 in-a-row win performance in group B. This was the very first time that two Turkish teams played against each other. Beşiktaş lost against Galatasaray Cafe Crown and eliminated in quarters. In the league, team finalized the regular season on top place and been a part of Play-offs. After the elimination of Beşiktaş Cola Turka in the quarters, the declaration was released that Ergin Ataman no more coaching Beşiktaş Cola Turka.
Efes Pilsen
A week later, he signed a two-years contract with Efes Pilsen, where he had worked from 1999 to 2001. Ataman have reached the major achievements in 2008–09 season with winning Turkish League, Turkish Cup, and Turkish President's Cup championships. On June 4, 2010, he left the Efes Pilsen.
Return to Beşiktaş
He signed a two-years contract with Beşiktaş in the January 2011. In the 2010–11 season, he didn't win the cups with Beşiktaş. And next season, he won the Turkish Cup in February 2012. Subsequently, he won the EuroChallenge title against Elan Chalon in the final on April 29, 2012. And finally, he won the Turkish League championship victory against Anadolu Efes in the playoff finals on June 11, 2012.
He signed a multi-year contract with Galatasaray Odeabank on June 22, 2012. He won the Turkish League championship victory against Banvitspor in the playoff finals on June 15, 2013. In the beginning of 2014–15 season, Galatasaray struggled financially and eventually in the results. Several players boycotted training and also some were injured, which led to frustration and conflicts in the team. On October 19, 2014, Ataman was involved in the incident with then-Galatasaray player Nolan Smith, who threw the towel while being subbed out from the game against Banvit. The player parted ways with the team the following week. On November 21, 2014, in the press-conference after the EuroLeague game against the Serbian team Crvena zvezda in Istanbul, Ataman got negative publicity in Serbia, for calling 300–400 Zvezda fans Delije the "terrorists". He also stated that they were "attacking our police and our fans with torches and stones" and that he was "worried as a citizen for his and others safety". All these comments came in line with the killing of Crvena zvezda fan by Galatasaray supporters in fan violence before the game. Even Serbian PM Aleksandar Vučić reacted to that comment, saying that "Ataman is no longer welcome in Serbia". Ataman later apologized for his comments, saying that "all the remarks were made before learning it ". On June 6, 2015, he signed a two-year extension with the club, reportedly worth half million euros per season. On April 27, Ataman's team Galatasaray Odebank defeated Strasbourg in Abdi İpekçi Arena and won the EuroCup title. With this win he reached his 3rd European-wide championship as a head coach.
Anadolu Efes
In December 2017, Ataman signed a contract with Anadolu Efes. In 2018–19 season, Ataman led Anadolu Efes to the 2019 EuroLeague Final Four, where they lost in the final game to the CSKA Moscow. On May 23, Ataman signed a two-year contract extension with the Anadolu Efes.
