  The prospects for the measurement of $B_{s}^{0}$ oscillations with the ATLAS
detector at the Large Hadron Collider are presented. $B_{s}^{0}$ candidates in
the $D_{s}^{-} \pi^{+}$ and $D_{s}^{-} a_{1}^{+}$ decay modes from semileptonic
events were fully simulated and reconstructed, using a detailed detector
description. The sensitivity and the expected accuracy for the measurement of
the oscillation frequency were derived from unbinned maximum likelihood
amplitude fits as functions of the integrated luminosity. A detailed treatment
of the systematic uncertainties was performed. The dependence of the
measurement sensitivity on various parameters was also evaluated.
