The bed frame includes a base frame and an articulating upper frame. The base frame includes a head end, a foot end and oppositely-disposed longitudinally extending sides. The articulating upper frame or deck comprises an upper body section, a seat section, a thigh section, and a lower leg section. These frame sections are longitudinally spaced apart and transversely extended, and at least the upper body, thigh and lower leg sections are movable with respect to the seat section to provide for the articulating movement. The articulating upper frame is mounted on the base frame for longitudinal shifting of the articulating upper frame relative to the base frame. A drive assembly for raising and lowering the upper body section relative to the base frame includes linkage connected to the upper body section such that, tilting movement of the upper body section shifts the articulating upper frame longitudinally relative to the base frame. A second drive assembly for raising and lowering the thigh section relative to the base frame includes linkage connected to the lower leg section such that, when the thigh section tilts upwardly, the lower leg section tilts downwardly. In accordance with further aspects of the bed frame, a drive assembly for longitudinal shifting of the upper frame relative to the base frame includes linkage connected to the upper body section such that longitudinal shifting of the upper frame relative to the base frame results in tilting movement of the upper body section.