  Merging rates of compact binaries (double neutron stars or black holes) are
calculated based on the modern concept of binary stellar evolution. It is found
that the initial laser interferometers with an rms-sensitivity of $10^{-21}$ at
the frequency 100 Hz can detect 10-700 black holes and only \sim 1 neutron star
coalescences in a 1-year integration time. Implications of the evolutionary
effects to the cosmological origin of GRB are also discussed.
