  The unique features (super-low background and large sensitive volume) of the
CTF and BOREXINO set ups are used in the CAMEO project for a high sensitivity
study of 100-Mo and 116-Cd neutrinoless double beta decay. Pilot measurements
with 116-Cd and Monte Carlo simulations show that the sensitivity of the CAMEO
experiment (in terms of the half-life limit for neutrinoless double beta decay)
is (3-5) 10^24 yr with a 1 kg source of 100-Mo (116-Cd, 82-Se, and 150-Nd) and
about 10^26 yr with 65 kg of enriched 116-CdWO_4 crystals placed in the liquid
scintillator of the CTF. The last value corresponds to a limit on the neutrino
mass of less than 0.06 eV. Similarly with 1000 kg of 116-CdWO_4 crystals
located in the BOREXINO apparatus the neutrino mass limit can be pushed down to
m_nu<0.02 eV.
