Carlos Melero rode on the Spanish team that placed sixth at the 1971 World Championships in the team time trial. Melero also finished fourth that year in the Tour de l’Avenir. After the 1972 Olympics he turned professional and was a domestique in the pro peleton, his only major podium finish coming in 1974 with a second place at the Tour d’Aragon. Melero rode in the Tour de France five times, with a best finish of 28th in 1975. He also rode the Vuelta d’España four times, placing 22nd in 1979 and 23rd in 1977.