We have estimated the quality factor, Qβ for shear-waves for western and central Slovenia for five frequency bands centred at 0.8 Hz, 1.5 Hz, 3.0 Hz, 6.0 Hz and 12.0 Hz. We used 150 high quality broadband waveforms, from 15 shallow (depth ≤ 8Km) aftershocks of the 2004 (MW 5.2) krn mountain earthquake sequence in NW Slovenia. Magnitudes (ML) range from 2.5 to 3.5 and epicentral distances from 16 to138 km. Our results show that Qβ varies with frequency f according to the power law Qβ=83f0.80 or Qβ-1=0.012f0.80. Comparing our results to those previously obtained for the region of Friuli-Venezia-Giulia in the Southern Alps, both show high values of seismic wave attenuation that is typical of seismogenic active regions and among all sets of data we can observe a good agreement.