Prevention of spontaneous preterm birth is an important public health priority. Pessary may be a potential therapy in cases of cervical insufficiency, in singleton and multiple gestations. Availability of transvaginal sonography for accurate assessment of cervical length is allowing for the tailoring of therapy to a more specific subset of patients who may benefit from this treatment. Pessary therapy is attractive given the favorable side effect profile, low cost, and ease of placement and removal. Large randomized trials are ongoing to validate initial favorable findings.