Unión Deportiva Cornellà was founded on 29 April 1951 by the merging of Club Atlético Padró and Academia Junyent.[3] Since its foundation the club participated in regional competitions and Tercera División until the season 2013/2014, when it achieved the historic promotion to the Segunda División B.[4]
On 6 January 2021, Cornellà upset La Liga giants Atlético Madrid by a score of 1–0 in the second round of the Copa del Rey.[5] They were eliminated in the following round by Barcelona, as the final score was 2–0 after extra time.[6]