The invention relates to a method and an arrangement for braking a synchronous motor (4) used with a frequency converter (2). The braking current of the motor (4) is controlled by connecting only the negative changeover contacts (10) of the inverter (16) of the frequency converter (2) or alternatively by connecting only the positive changeover contacts (17) of the inverter (16) of the frequency converter. The arrangement comprises a control (3), which is arranged to control in a braking situation only the negative changeover contacts (10) of the frequency converter (2) or alternatively only the positive changeover contacts (17) of the frequency converter (2).