Costa departed the Spanish captital two years ago for a fee reported to be worth £32million and began life at Chelsea in fine style, bagging 20 goals in his debut season for the Londoners.
However, things did not go quite to plan in the following campaign and it was suggested that a move back to Atleti could be what Costa needs in order to reignite his career although Conte is having none of it.
"Diego is our player, he's a fantastic player for me. He's a fantastic player with fundamental importance," he told a news conference on Tuesday.
"For me it's not about the possibility to go to this team, or that team, we want him to stay with us. He's working very hard and he seems very happy to work with his team-mates and a new idea of football.
"The most important thing is that Diego Costa is a Chelsea player."