In 1989, the Main Branch of the Cobb County/Marietta Public Library vacated the Post Office building on Atlanta Street, moving into a newly erected building on Roswell Street. During this same time in September, the Marietta/Cobb Fine Arts Center changed its name to the Marietta/Cobb Museum of Art.
On April 5, 1990 the Marietta/Cobb Museum of Art officially took over the original Post Office building chosen by the Cobb County Commission.