  We discuss the feasibility of the observation of the signal from $B_c$ mesons
in the ATLAS experiment of the LHC collider at a luminosity of ${\approx}\
10^{33}$cm$^{-2}$s$^{-1}$. In particular we address the decay mode
$B_c{\rightarrow}J/\psi \pi$ followed by the leptonic decay
$J/\psi{\rightarrow}\mu^+\mu^-$, which should permit an accurate measurement of
the $B_c$ mass. We performed a Monte Carlo study of the signal and background
concluding that a precision of $40$ MeV for the $B_c$ mass could be achieved
after one year of running.
