The rodenticidal effect of ethanolic leaves extract of Oshar, Calotrips procera (Ait.) was studied comparatively with zinc phosphide under laboratory and field conditions at (Qaha region) Qaluobia Governorate against the Norway rat, Rattus norvegicus (Berkenhout). Results showed that zinc phosphide was more toxic than Oshar extract whereas the acute oral LD₅₀ values were 0.27 and 88.0 mg/kg b.w., respectively. The efficiency test showed that in non-choice and free-choice feeding test a bait containing 1 % either zinc phosphide or Oshar plant extract gave 100 % mortality with short time to death for zinc phosphide treatment. Oshar bait was more palatable to mice than zinc phosphide with 56.2 and 40.6 % bait acceptance, respectively. Under the field condition, zinc phosphide caused 78.4 5 % reduction whereas Oshar plant extract reduced 66.5 % the population of the Norway rat, respectively.