Ruffin joined the Peninsular War, leading I Corps into Spain in September 1808. He served at Somosierra, Ucles, Medellin and Talavera, before commanding one of Victor's divisions at the Battle of Barrosa on 5 March 1811. During the battle for the Barrosa Ridge, Ruffin was shot through the neck, causing him to be paralysed. He was captured by the British army and shipped to England. Although he appeared to be recovering from his wound, he suffered a relapse on the voyage and died aboard the transport "Gorgon" on 15 May.