Tests were conducted using 0.05% warfarin baits which were put into polietilinized paper bags with corn oil as attractants, in order to control cotton rats (Sigmodon hispidus major) through-out 4,000 ha. of crops in the Sinaloa State. Both the effectiveness of the warfarin bait and the security and efficiency of the handling of the polietilinized paper bags was demonstrated. Furthermore, the tests showed that there were economic advantages in using the warfarin baits instead of the zinc phosphide baits; to the extent of a 46.67% saving in the control expenses.