The isomeric yield ratios are measured for 97 Nb fragments obtained at the bremsstrahlung photofission of 235 U and 238 U nuclei with gamma-quantum end-point energies of 10.5, 12.0, and 18.0 MeV. The mean angular momenta of primary fission fragments are determined, by using the generalized Huizenga-Vandenbosh statistical model and with the help of TALYS 1.6 and EMPIRE 3.2 codes. K e y w o r d s: photofission, isomeric ratios, mean angular momenta of fission fragments.