Preterm birth remains a considerable public health concern and priority. Little headway has been made in the prevention of preterm birth despite considerable research in this area. New ideas and treatments are desperately needed. The pessary has emerged as a possible treatment for the prevention of preterm birth in both singleton and twin gestations. It appears to be low cost with minimal side effects. This review focuses on the available evidence for the use of cervical pessaries for the prevention of preterm birth, especially in a high-risk population with a shortened cervical length. Larger scale randomized-controlled trials are warranted before incorporation of the pessary into standard obstetrical practice. © 2014, Lippincott Williams & Wilkins.