Cha Seung Baek (born May 29, 1980 in Busan, South Korea) is a Major League Baseball pitcher for the San Diego Padres.

Baek graduated from Busan High School, Busan, South Korea in 1998. He was signed by the Seattle Mariners as an amateur free agent on September 25, 1998. He made his MLB debut on August 8, 2004 against the Tampa Bay Devil Rays. In the 2004 season, he pitched in seven games (starting five), winning two and losing four, and had a 5.52 ERA overall.

Baek was non-tendered by the Mariners in December 2005 following a disappointing year in Triple-A with the Tacoma Rainiers. Baek returned to the Rainiers for the 2006 season. He posted an 11-4 record with a 2.80 ERA, which earned him a recall to the Mariners in August 2006, following their trade of Jamie Moyer to the Philadelphia Phillies. After that, he was moved to being a relief pitcher and spot starter for the Mariners.