Method and apparatus for preventing bed sores in a bedridden patient. A low air loss bed is provided including a frame, a first set of substantially rectangular air bags for supporting a patient thereon mounted transversely on the frame, and a second set of substantially rectangular air bags for supporting a patient thereon mounted transversely on the frame, and all of the air bags are connected to a gas source. The conformation of the air bags is such that, when the first set of air bags is inflated, the patient supported thereon is moved toward the first side of the frame of the low air loss bed and, when the second set of air bags is inflated while the first set of air bags is deflated, the patient is moved toward the second side of the low air loss bed. The conformation of the air bags also retains the patient on the top surface of the air bags when the patient is rolled in one direction or the other.The first and second sets of air bags are mounted on a frame which is itself divided into sets of transversely mounted air bags so that the frame can be contoured to the patient's comfort. Also provided is means for additionally inflating the air bags under those portions of the patient which are heaviest when the frame of the bed is inclined for patient comfort.The method of the present invention comprises inflating a plurality of air bags to a selected pressure for supporting a patient thereon, inflating a first set of air bags to a pressure higher than the selected pressure to cause the patient support thereon to be rolled in a first direction on the air bags, and thereafter deflating the first set of air bags while inflating a second set of air bags to a higher pressure than the selected pressure to cause the patient to be rolled in a second direction on the air bags. A third set of air bags can be provided in which the selected pressure is maintained, thereby substantially immobilizing a portion of the patient'body.