An automatic transmission control system for controlling oil pressure of a frictional engagement device in accordance with an input torque to an automatic transmission, comprising: a plurality of input torque estimating devices for estimating the input torque to the automatic transmission; a first oil pressure determining device for determining the oil pressure on the basis of the input torque to the automatic transmission, as estimated by any of the input torque estimating device; a trouble deciding device for deciding a trouble about the input torque value estimated by any input torque estimating device; and a second oil pressure determining device for determining the oil pressure on the basis of the input torque to the automatic transmission, as estimated by another input torque estimating device, if the trouble deciding device decides a trouble about the input torque value estimated by any input torque estimating device.