A statement on Rayo Vallecano's official website has confirmed that Leo Baptistao has signed a five-year contract with Atletico Madrid.
The 20-year-old, who scored seven goals for Rayo this season, will officially complete his move to the Copa del Rey winners when the summer transfer window opens next month.
"The club thanks Leo Baptistao for the professionalism and dedication he showed in the years he spent defending the Rayo shirt," the statement read.
"We wish him the best of luck, both personally and professionally, for the next stage of his career."
The Brazilian forward is currently recovering from a broken collarbone, but is expected to be fit to start pre-season training with his new club in July.