Cancer is not a single disease, but a large group of diseases characterized by uncontrolled, rapid and pathological proliferation of abnormally transformed cells. Pyrazoline is a five-membered heterocyclic ring having two adjacent nitrogen atoms within the ring. It has only one endocyclic double bond and is basic in nature. The present study involves synthesis of 1-substituted-2-thienyl-5-(4-chlorophenyl) pyrazoline derivatives. The synthesized compounds were subjected to anticancer screening against SK-OV-3 cells line to determine the growth inhibitory effects of the compounds. Amongst all the derivatives in series (6a-j), the pyrazoline derivatives exhibited potent anticancer activity. All synthesized compounds possessed good to moderate anticancer activity. Compounds 6b and 6c at concentration 80 μg/mL possessed % control growth inhibition comparable to standard drug andriamycin. The order for the % control growth inhibition of SK-OV-3 was found to be 6h> 6j> 6f> 6i> 6e> 6g> 6d> 6a. All the compounds inhibited 50 % of the cell growth at the conc.