At the 2004 Summer Olympics in Athens, Tregubova qualified again for the 50 m freestyle by eclipsing a FINA B-cut of 26.90 from the Russian Open Championships in Moscow. Swimming in the same heat as Sydney, she picked up a second spot over Aruba's Roshendra Vrolijk by 0.03 of a second, outside her entry time of 28.40. Tregubova failed to advance into the semifinals, as she placed forty-eighth overall out of 75 swimmers on the last day of preliminaries.