Abstract: A bi-fold door assembly which includes an overcenter spring-biased hinge assembly comprising first and second hinge members including first and second mounting positions fixedly connected with first and second door panels respectively, interengaging axially aligned hinge portions constructed and arranged to receive a hinge pin therethrough establishing a vertical hinge axis between the two door panels and a spring constructed and arranged to provide oppositely directed spring forces. Each spring is constructed and arranged with respect to the first and second hinge members so that the opposed spring forces provided by the spring are applied to the first and second hinge members to bias the first and second door panels into the closed position when the door panels are near the closed position and to bias the first and second door panels into the opened position when the door panels are near the opened position.