Magneto-optical (MO) properties of ferromagnetic Co(2)YGe full-Heusler alloys (Y=Fe and Mn) are investigated by the first principles electronic structure calculations using the highly accurate FLAPW method within GGA + U approach. The polar magneto-optical Kerr angles are calculated by solving Kubo's linear response formula using the FLAPW eigenstates and eigenfunctions to obtain the optical conductivity by interband transitions. The typical features of polar Kerr rotation of transition metals with two major peaks were obtained while the low energy spectra are enhanced largely at 1-2 eV region compared to GGA results. Detailed electronic structures analysis revealed that this enhancement is due to the decreased interband transitions by reduced diagonal optical conductivity. Results indicate that the MO spectra can be used to determine the appropriate correlation level for the present alloys. (C) 2011 Elsevier B.V. All rights reserved.