Oxygen abundances in the interacting galaxies NGC 4631 and NGC 4656 were derived. The spectra of seven H II regions (four H II regions in the NGC 4631 galaxy and three H II regions in the NGC 4656 galaxy) which contain auroral oxygen line [O III] λ 436.3 nm were revealed in the database of the digital sky survey Sloan II (SDSS II — the Sloan Digital Sky Survey). The intensities of the spectral lines were measured. The oxygen abundances in the H II regions were derived using these measurements. The parameters of the radial oxygen abundance distribution (the central oxygen abundance and slope of the radial gradient) in the discs of these galaxies were estimated. The position of these galaxies on the luminosity — metallicity diagram is examined.