Guiscardo competed for Argentina in the women's 100 m breaststroke at the 2008 Summer Olympics in Beijing. Leading up to the Games, she crushed the Argentine record time of 1:10.38 to satisfy the FINA B-standard (1:11.43) at the Maria Lenk Trophy in Rio de Janeiro, Brazil. Swimming as the fastest entrant in heat four, Guiscardo held off a quick-charging Brazilian Tatiane Sakemi throughout the race to keep the fourth spot by 0.32 of a second in 1:11.43. Guiscardo failed to advance into the semifinals, as she placed thirty-seventh overall out of forty-nine swimmers in the prelims.