Hascall Hall is a historic institutional building located on the campus of Colgate University at Hamilton in Madison County, New York.

The original section features a hipped roof of slate, eyebrow windows, and a large semicircular archway entrance.

[1] Probably the most significant science student ever to attend classes in this building, referred to commonly as "Old Bio", was Oswald Avery, class of 1900, who discovered that DNA was responsible for the transference of genetic information while later working on carefully executed experiments at the Rockefeller Institute on specimens of pneumonia found in victims of the 1918 flu outbreak.

After Olin hall was built at the end of the Colgate quadrangle for the biological sciences, "Old Bio" was used as an art studio in the 1970s.

The interior was later renovated, converted back into small classrooms, and renamed Hascall Hall.