La Liga side Deportivo La Coruna sold striker Lucas Perez last season for £17.1m but he failed to make an impact at the Emirates.
The 28-year-old Spaniard scored seven goals for the Gunners but after the arrival of Alexandre Lacazette has fallen further down the pecking order.
Newcastle were interested in the player but he was only interested in a return to his former club.
“Lucas Perez has rejoined Spanish side Deportivo de La Coruna on loan for the 2017-18 season,” a statement read.
“Lucas returns to Deportivo, where he enjoyed a prolific campaign in 2015-16, equalling a club record for goals scored in successive games.
“The 28 year-old has netted a total of seven times for the club in 21 appearances to date. We all wish Lucas well for his time with Deportivo this coming season.”