  We investigate the possibility to measure the top quark mass using the
collider variable $m_{T2}$ at the LHC experiment. Monte Carlo studies of
$m_{T2}$ are performed with the events corresponding to the dilepton decays of
$t\bar{t}$ produced at the LHC with 10 $fb^{-1}$ integrated luminosity. Our
analysis suggests that the top quark mass can be determined by the $m_{T2}$
variable alone with a good precision at the level of 1 GeV.
