  We report the detection of the Sc-44 nuclear decay lines at 67.9 keV and 78.4
keV associated with the nuclear decay of Ti-44 in Cassiopeia A. The line
emission was observed by the PDS instrument on board BeppoSAX, which recently
observed the supernova remnant for over 500 ks. The detection of the line
emission with a flux of (2.1 +/-0.7) 10^{-5} ph/cm^2/s in each line (90%
confidence) is at the 5 sigma significance level, if we can assume that the
12-300 keV continuum is adequately represented by a single power law. However,
as the nature of the continuum is not clear we investigate various other
possibilities. A more conservative estimate of the line flux is made by
assuming that a power law continuum is at least a good approximation to the
continuum emission for a narrower 30-100 keV energy range. With this limitation
the measured line flux is (1.9 +/- 0.9) 10^{-5} ph/cm^2/s, with the detection
still at the 3.4 sigma significance level. We suggest that together with the
CGRO-COMPTEL measurement of the Ca-44 line at 1157 keV of (3.5 +/- 0.9) 10^{-5}
ph/cm^2/s a flux for all three lines of (2.5 +/- 1.0) 10^{-5} ph/cm^2/s for Cas
A can be adopted. This implies an initial Ti-44 mass of (0.8 - 2.5) 10^{-4}
Msun.
