Cucurbita moschata (CM) is an indigenous plant in Iran, which the plant has been applied as an antihypertensive, anticancer, antiparasitic, antiviral, antifungal, antioxidant, and antiflammatory agent in Iran. In comparison to many other pharmaceutical-industrial plants, there is a very little data about antibacterial activities of CM oil collected from Iran. Hence, the aim of the current study was evaluation of antibacterial activities of the oil on Escherichia coli O157:H7 (ATCC No. 25922) (EC) in west of Iran (In Kermanshah). The antibacterial effects of CM oil was assessed by macro-dilution method in Mueller-Hinton broth medium, agar disk and well diffusion methods. The results demonstrated that the oil of CM have prevented the growth of EC and killed it. Also, by incrementing the concentration of the CM oil, the inhibition zones incremented. We believe that the article provide support to the antibacterial properties of the oil. In fact, this work indicate that the oil of CM can be beneficial as medicinal composition. Fractionation of active molecules will be the future work to peruse.