We characterize the stellar populations in the nuclear region of the barred spiral galaxy NGC 4900 using the integral field spectrometer OASIS and the synthesis code LavalSB and the code from Mollá & García-Vargas (2000) for the young (<10 Myr) and the old stellar populations, respectively. The high spatial resolution of the instrument allows us to find an old population uniformely distributed and younger regions located at the end of the galaxy bar and on each side of a nuclear bar.