ABSTRACT Cucurbita pepo (C. pepo) is a perennial creeping herb of Gourd family Cucurbitaceae. The seeds of which contain various phytoconstituents such as fixed oils, tocopherols, vitamins and minerals. The aim of this study was to investigate cytotoxic properties of the different extracts of the seeds of C.pepo and their various fractions by using brine shrimp lethality bioassay. The methanolic extract, n-hexane extracts, ethanolic, and chloroform fraction of methanol extract of seeds of C. pepo exhibited the most significant cytotoxic properties with the LC50 values of 3.125μg/ml, 1.67μg/ml, 5.51μg/ml and 6.25μg/ml respectively. Moderate cytotoxicity was showed by chloroform and ethanol fractions of seeds of C. pepo having LC50 values of 6.25 μg/ml and 5.51μg/ml. The prominent result was obtained for n-hexane extract (LC50 value 1.67μg/ml). The results of this investigation are highly promising, where vincristine sulphate (LC50 value 1.5μg/ml) was used as the positive control.