At the 2000 Summer Olympics in Sydney, Lopez decided to drop two of his events from Atlanta and experiment with the 100-meter breaststroke. He finished in a first-place tie with Latvia's Valērijs Kalmikovs on the fourth heat with a time of 1:04.02. In the 200-meter individual medley, he raced to a fourth seed in heat three by 0.07 seconds behind South Korea's Han Kyu-Chul in 2:06.49. Lopez did not qualify for the semifinals, finishing thirty-fourth each in all of his events from the heats.