Frederick Helsher Rath Sr. (born September 1, 1943) is a former Major League Baseball pitcher who appeared in 8 games for the Chicago White Sox during the 1968 and 1969 seasons.

Rath, who attended Baylor University, was drafted by the White Sox in the 4th round of the 1965 amateur draft and made his major league debut 3 years later.

Following the 1970 season he was traded to the California Angels for John Purdin, but never appeared in a major league game again.

Rath's son, Fred Rath Jr., also had a brief major league career, appearing in two games for the Colorado Rockies in 1998.

This biographical article relating to an American baseball pitcher born in the 1940s is a stub.