Abstract: An automatic tire inflation system including an air pump, a pressure sensor, a microprocessor and a rechargeable battery power supply all housed in a water resistant housing. The housing conforms to the diameter of the rim of a standard vehicle tire and is held to the tire by rim retaining fingers. A recharging jack is mounted inside the housing and is accessed through an aperture on the housing which is sealed by a removable waterproof cover. The microprocessor monitors air tire pressure being sent from the pressure sensor and activates the air pump when the pressure is determined to be too low by the microprocessor. The air pump turns off when the air tire pressure reaches a predetermined set point. The rechargeable battery is recharged by a standard charging device attached by a plug to the recharging jack. Similar automatic tire inflation systems can be mounted to each tire of the vehicle.