Laboratory studies were carried to investigate the susceptibility of three anticoagulant rodenticides, Brodifacoum, Chlorophacinone and Warfarin on both sexes of albino Norway rat, R. norvegicus which were fed on either equally mixture of maize and wheat or vegetables. The obtained results could be summarized in the following:- A- Determination of LD values of three anticoagulant rodenticides:-                 The final results proved that males of R. norvegicus which fed on either mixture of wheat and maize or vegetables were more tolerant than females approximately. In addition, the gained figures cleared that both sexes of R. norvegicus which fed on mixture of wheat and maize were more susceptible to Chlorophacinone than Brodifacoum and Warfarin. In spite of, the tested animals which fed on vegetables were more susceptible to Brodifacoum, they had tolerance to Warfarin. B- Effect of ¹/₁₀ of LD values of the tested anticoagulant rodenticides on bleeding time of both sexes of R. norvegicus:-                 The results in case of feeding on maize and wheat showed a highly significant differences between rodenticides after 24, 48 and 72h at ¹/₁₀LD₉₀ and ¹/₁₀LD₅₀, while there was no any significant difference after 48 and 72h post-treatment.                 The effect of ¹/₁₀LD₉₀ and ¹/₁₀LD₅₀ of the tested rodenticides on bleeding time of R. norvegicus which fed on maize and wheat could be arranged according to their effectiveness in descending order as follows; Brodifacoum > Chlorophacinone > Warfarin. Also, results showed no significant difference between replicates and sexes at the three periods of bleeding time whereas, in the case of feeding on vegetables, the results revealed a highly significant differences between treatments at the dose of ¹/₁₀LD₉₀. Also, the results showed a highly significant differences between the investigated doses during three periods in the two cases of feeding except for the Warfarin treatment after 72h.