The Danubio young talented centre-back will join the Copa del Rey finalists in the summer on a five-year deal
The talented young Uruguayan has been linked with a host of clubs in recent times but it is the Colchoneros who have secured his signature. Gimenez is most comfortable playing as a centre-half.
Gimenez, 18, joins fellow countrymen Diego Godin and Cristian Rodriguez at the Estadio Vicente Calderon.
The deal was completed on Wednesday after Gimenez passed his medical tests and he will return to his homeland before joining up with Atletico again in the summer.
Diego Simeone's men currently occupy the last automatic Champions League place in Spain, with a comfortable 13-point advantage over fourth-placed Real Sociedad.