A sofa-bed includes: a frame with opposed arms; a backrest operatively connected to the frame; a seat; a subseat hinged to the seat and pivotable relative thereto; an extension-assist mechanism attached to the frame and at least one of the seat and the subseat; and a folding-assist mechanism attached to the frame and at least one of the subseat and seat. The frame, backrest, seat and subseat are configured to move between a folded position, in which the backrest is generally upright, the seat is generally horizontal, and the subseat is generally horizontal and positioned beneath the seat in a first inverted orientation, and an unfolded position, in which the backrest, subseat and seat are generally horizontal, and the subseat is positioned between the backrest and the seat in a second non-inverted orientation. The folding-assist mechanism is configured such that the sofa-bed is biased toward the folded position as the sofa-bed moves from the unfolded position toward a first intermediate position. Also, the extension-assist mechanism is configured such that the sofa-bed is biased toward the unfolded position as the sofa-bed moves from a second intermediate position toward the folded position.