Abstract. A crucial issue in the operation of Imaging Atmospheric Cerenkov Telescopes is the optimization of the trigger condition, which is based on the discriminated signals of the individual pixels. The telescope should accept gamma-ray images at the lowest possible energies and also suppress background proton-induced showers as much as possible.Using the CORSIKA air shower code we have carried out detailed Monte-Carlo simulation studies with regard to optimizing the trigger field of view (FoV)of the TACTIC telescope. The results of this study suggest that, a trigger FoV corresponding to the innermost (11$\times$11) pixels is quite optimum for accepting most of the events from a point gamma-ray source. This optimized FoV not only reduces the triggers generated due to chance coincidence but also the triggers from the cosmic ray background leading to improved sensitivity for TACTIC telescope. The results of the Monte-Carlo simulation studies on the performance of the TACTIC telescope at several zenith angles for various trigger FoV will be presented.