A new reduction and a new analysis of a rich series of high-S/N spectra of the bright star κ Sco is carried out to test the technique of spectral disentangling in the case when one of the components is a non-radial oscillator. We improve the orbital elements of the system and find the basic physical properties of the binary to be Teff = 24 500 K, masses of 10.7-11.9 M&sun; and 9.6-10.7 M&sun; and the primary radius and rotational period of 7-8 R&sun; and 3d.56-3d.68, respectively. This also implies log g ,= 3.70-3.78 [cgs]. KOREL disentangling is applied and we find that it worked properly and was not misled by the complex line-profile variability of the pulsating primary. Moreover, the pulsational frequencies are detected via the period search in the line intensities and radial-velocity residuals of the primary derived by KOREL and in the time series of residual spectra in the rest frame of the primary after KOREL disentangling. This constitutes a much better starting point to interpret the complex pixel-by-pixel variations of the disentangled profiles of the primary in terms of stellar oscillations and/or additional rotational modulation than the original spectra before disentangling. Based on spectral observations obtained at ESO with the CAT/CES, La Silla, Chile.