Marcelo Augusto Tomazini (born December 18, 1978, in São Paulo) is a male breaststroke swimmer from Brazil.

At the 1999 Pan American Games in Winnipeg, Manitoba, Canada, Tomazini teamed with Alexandre Massura, Fernando Scherer, and Gustavo Borges[1] to compete in the 4×100 meter medley.

[2] When Tomazini competed in the 200-metre breaststroke, his time of 2:17.04 did not win a medal (finished 4th), but broke the South American record.

On November 17, 2001, he broke the short-course South American record in the 200 meter breaststroke, with a time of 2:10.79.

[8] On March 17, 2002, Tomazini again broke the South American record in the 200-metre breaststroke (Olympic pool), with a time of 2:16.21.