Many commercial electric power-assisted bicycles must be equipped an expensive torque sensor to measure the pedaling torque of the user. If it is possible to measure the pedaling torque without such an expensive torque sensor, the cost of these bicycles will be reduced. In this paper, a method for estimating the pedaling torque that is applied in a sloped environment is proposed. To increase the estimation accuracy, the parameter identification of the motor is presented. The validity of the proposed method is shown thorough experiments with motor assistance on a sloped environment.