  We present the results of the UBVRcIc surface brightness profiles
decomposition of the Seyfert galaxies III Zw 2, Mrk 506 and Mrk 509. The
profiles were modelled as a sum of a Gaussian, a Sersic law and an exponent. A
Ferrers bar and a Gaussian ring were added to the model profiles of III Zw 2
and Mrk 506, respectively. The parameters and the total magnitudes of the
structural components were derived.
