A series of 3-arylidene-5(substituted phenyl)-2(3H)-pyrrolones have been evaluated for their in vitro anthelmintic activity against two species of earthworms i.e. Pheretima posthuma and Perionyx excavatus. The anthelmintic activity of ten pyrrolones (I-X) was determined by recording the mean paralyzing and death times of the worms at concentration of 2 mg/mL. The screened compounds showed appreciable anthelmintic activities against both types of worms.