Sergei Valentinovich Zabolotnov (also Sergey, Russian: Серге́й Валентинович Заболотнов; born 11 August 1963, is a former backstroke swimmer from the USSR.

[3] The time of 2:00.42 was achieved on 4 July 1983 at Edmonton, Canada, when winning a gold medal whilst competing in the World University Games.

After missing the 1984 Summer Olympic Games in Los Angeles of late July and early August due to the eastern bloc boycott, Zabolotnov competed at the Friendship Games in Moscow, USSR, winning the gold medal for the 200 m backstroke in a world record time of 1:58.41 on 21 August 1984.

Rick Carey won the gold medal for the 200 m backstroke in Los Angeles in a time of 2:00.23, three weeks before Zabolotnov's world record swim.

Zabolotnov competed at the 1988 Summer Olympic Games in Seoul, South Korea, in both the 100 and 200 m backstroke, finishing fourth in each.