The losses of a new axial flux permanent magnet generator (AFPMG) have been explored theoretically. The machine is designed and analyzed by a electromagnetic finite element method (FEM) simulation package. The suggested generator is three phase with two rotors and a stator between them. The rotors have 32 rare earth disctype magnets at two sides and the stator has 24 coils. The losses are calculated from the FEM simulation package over the entire volume of the machine. It has been observed that the losses increase with the rotor speed. The core loss becomes higher than the copper loss for no-load operation. On the other hand, the copper loss becomes larger than core losses in the resistive load operation. The efficiency of the machine is found as 92.5 % for its rated speed 1000 rpm.