Warfarin was evaluated in laboratory against Indian gerbil,Tatera indica and desert gerbil,Meriones hurrianae. Chronic LD50 for the two species was found to be 4 × 19·1 and 4 × l5·9mg/kg respectively. Feeding for 14 days on 0·025% warfarin treated bait provided complete kill in the gerbils but the poisoned bait was less palatable than the plain bait. A period of 18 and 19 days feeding on 0·025% waifarin bait was found suitable to detect resistance to warfarin amongT. indica andM. hurrianae respectively.