Arsenio Alexander López Rosario (born May 3, 1979), also known as Alex Lopez, is a Puerto Rican former swimmer and three-time Olympian who specialized in breaststroke and individual medley events.

[2][3] He also placed seventeenth, as a member of the Puerto Rican team (including finalist Ricardo Busquets), in the 4×100-meter freestyle relay (3:28.27).

He cleared a FINA B-standard entry time of 1:04.01 from the 2003 Pan American Games in Santo Domingo, Dominican Republic.

[7] He challenged seven other swimmers in the same heat as Sydney, including four-time Olympian Ratapong Sirisanont (Thailand), who was later disqualified for a false start.

Lopez ended his third Olympic stint by sharing a thirty-fifth place tie with New Zealand's Ben Labowitch on the morning prelims.