The study was aimed at detecting the development of bait shyness towards zinc phosphide and vacor inMus platythrix and its persistence. Both the rodenticides induced poison aversion after single ingestion of sub lethal quantities, while bait shyness towards zinc phosphide lasted 170 days, vacor produced poison shyness persisted upto 120 days. Based on these results it may be concluded that poisoningM. platythrix with zinc phosphide and vacor should be done for a single day only and residual population be killed by other means. Secondly control ofM. platythrix by zinc phosphide poisoning should not be repeated till 170 days and that of vacor till 120 days.