The aim of this study is to evaluate the estrogenic activity of Cucurbita pepo seed extract which includes β-sitosterol and other phytosterols. Sample was extracted from Cucurbita pepo seed by supercritical carbondioxide method and resuspended with ethanol. Estrogenic activity was measured by recombinant yeast assay which detects estrogenic activity using recombinant yeast with high level of estrogenic receptor. However, estrogenic activity of pumpkin seed extract was not found in this study. Based on this data, pumpkin seed extract will not cause estrogenic disturbance.