The root parasitic weed Orobanche cumana (sunflower broomrape) constrains sunflower (Helianthus annuus L.) production in many areas of the world. A seed germination experiment, a co-culture experiment, and a pot experiment were conducted to study the effect of some soilborne antagonistic microorganisms on O. cumana. Results showed that culture filtrate of Streptomyces enissocaesilis significantly reduced the germination rate of O. cumana seeds both in the seed germination experiment and the co-culture experiment, with more than 50 and 40 % (after cultivation for eight days) reduction respectively over the control. In the pot experiment, applying S. enissocaesilis reduced the epigaeous number of O. cumana tubercles by 47.5 % after 130 days. Furthermore, S. enissocaesilis also increased polyphenol oxidase activity in sunflower roots and improved the beneficial microflora in the rhizosphere soil of sunflower. Selecting biocontrol agents from soilborne antagonistic microorganisms might be a promising strategy for controlling O. cumana.