Phosphorylated insulin-like growth factor binding protein-1 (phIGFBP-1) is secreted by decidual cells and may leak into cervical secretions during detachment of the fetal membrane. The aim of this study was to determine whether a rapid bedside test for phIGFBP-1 predicts preterm birth in women with preterm uterine contractions. This was a prospective study of pregnant women who sought medical care for symptoms of preterm labor. Cervical swabs were assayed for the presence of phIGFBP-1 by a rapid bedside test. Sixty-four patients were enrolled. Eleven of them (17%) delivered preterm (< 35 weeks). phIGFBP-1 in cervical secretions predicted preterm birth with a sensitivity of 72.7%, a specificity of 83.0%, a positive predictive value of 47.0%, and negative predictive value of 93.6%. Positive phIGFBP-1 bedside test in women with preterm uterine contractions may indicate a significant risk for subsequent preterm birth. The absence of phIGBP-1 is a reassuring sign that the likelihood of preterm birth is low.