The invention relates to a method and an arrangement for controlling a vehicle (100) during a downhill start. The vehicle comprises a service brake (131a, 131b; 132a, 132b; 33a, 133b), an engine (119) and a transmission (120) being arranged between the engine and at least one driven axle (123), wherein the service brakes, the engine and the transmission are controlled by an electronic control unit (140). The method involves registering that the vehicle is located on a downhill gradient; registering an action from the driver, indicating a request to start the vehicle; controlling the service brake to maintain the vehicle stationary during a predetermined time after the request before initiating a controlled service brake release; controlling a gradual release of the service brake in response to at least one detected first vehicle operating parameter; and releasing the service brake when detecting that a predetermined threshold for at least one second vehicle operating parameter has been attained.