  The final evolution of a binary black-hole system gives rise to a recoil
velocity if an asymmetry is present in the emitted gravitational radiation.
Measurements of this effect for non-spinning binaries with unequal masses have
pointed out that kick velocities $\sim~175$ km/s can be reached for a mass
ratio $\simeq 0.36$. However, a larger recoil can be obtained for equal-mass
binaries if the asymmetry is provided by the spins. Using two independent
methods we show that the merger of such binaries yields velocities as large as
$\sim 440$ km/s for black holes having unequal spins that are antialigned and
parallel to the orbital angular momentum.
