Alpha Tau Sigma (ΑΤΣ) was a professional medical fraternity that ceased operations in 1964.

[1] Its founders were Charles W. Barnes, W. S. Giddings, E. E. Loose, E. E. Ruby, and W. C. Warner[1] In April 1913, the fraternity rented rooms from the Axis Club in the Heinzeman-Swigert building in Kirksville.

[3][4] For several years, the fraternity occupied a three-story nineteen room house at 701 West Jefferson Street.

[1][9] Alpha Tau Sigma hosted medical lectures, musical performances, and social events.

[3][4][10][11] Its members also participated in Interfraternity Council baseball, basketball, football, softball, and volleyball tournaments.