Abstract: A vehicle automatic transmission control system which makes it possible to estimate an ATF temperature without using an expensive ATF temperature sensor. The estimation of the ATF temperature is configured such that based on the coolant temperature at engine starting, the temperature increase owing to heat inflow to the ATF per unit time and the temperature decrease owing to heat outflow from the ATF per unit time are calculated quantitatively and the sum of the calculated values is used to determine the estimated ATF temperature TATF. More specifically, when it is found that only a short time has passed between engine turnoff and restarting, the ATF temperature is estimated at engine restarting from the coolant temperature at engine turnoff, the estimated ATF temperature at engine turnoff and the coolant temperature at engine restarting.