Abstract: An inflation system for a mattress having a lower, water chamber and a coextensive upper, air chamber includes a pair of opposed blowers, a solenoid air valve, both manual and pressure activated switches and control circuitry for activating and deactivating the blowers in response to pressure within the air chamber sensed by the pressure switch or manual commands. The air/water mattress and inflation system of the present invention is suitable for long term care bedridden patients which have a tendency to develop decubitus ulcers and further facilitates entry, repositioning and egress from the water mattress when the air chamber is inflated.