Bismuth iron oxide BFO films were produced by the pulsed laser deposition technique. These films are a mixture of BiFeO3 ferroelectrical and Bi25FeO40 piezoelectrical phases. The ferroelectrical domain structure of these films was studied via contact resonance piezoresponse force microscopy (CR-PFM) and resonance tracking PFM (RT-PFM). The proportions of area of these BFO phases were derived from the PFM images. The ferroelectrical domain size corresponds to the size of the BiFeO3 crystals. The CR-PFM and RT-PFM techniques allowed us to be able to distinguish between the ferroelectric domains and the piezoelectric regions existing in the polycrystalline films.