OBJECTIVE: To evaluate the role of C-reactive protein and fetal fibronectin for patients with preterm labor and intact mxmbranes. STUDY DESIGN: The study group was comprised of sixty patients who presented to the Taegu Fatima Hospital between 24-36 gestational weeks who had a diagnosis of preterm labor. The study group underwent assay of C-reactive protein in the matemal serum, and fetal fibronectin from the external os and posterior fomix of the vagina by means of polyester fiber swabs. The study group was categorized to four groups according to the results of CRP and fetal fibronectin, that is 28 cases of CRP(-)/fetal fibronectin(-); group I, 12 cases of CRP(+)/fetal fibronectin (-); groupII, 9 cases of CRP(-)/fetal fibronectin(+); groupIII, 11 cases of CRP(+)/fetal fibronectin(+): grouplV, and the controls were 12 women without preterm labor. Outcome measures were occurrence of preterm delivery, the admission-to-delivery interval, matemal age and parity, fetal body weight, 1min/5min Apgar score, perinatal morbidity and mortality etc. Statistical analyses were performed by means of ANOVA test and Dunnett's t-test. RESULTS: The prevalence of study group were group I 46.7%, group II 20%, group III 15% and group IV 18.3%. There were no significant difference of matemal age, parity and gestational weeks at admission between study group and control group, but in all study group the admission to delivery interval was significantly shorter than that of control group. Analysis indicated also no significant difference of maternal hemoglobin between study group and conuol group but white blood cell count of group II and IV were significantly higher than that of control group. In perinatal outcomes, the mean birth weight and 1 minute Apgar score of study group except group I were significantly lower than those of control group but 5minutes Apgar score was lower only in group IV compared with control group. Perinatal morbidity and mortality of study group were higher than those of control group except group I. This study group was designed to compare the diagnostic performance of cervical fibronectin and of the serum CRP levels. The sensitivity and specificity of fetal fibronectin as a test to predict of preterm labor were 80% and 90%, which were slightly higher than those of CRP(70%, 78%). CONCLUSION: Both positive cervicovaginal fetal fibronectin and positive C-reactive protein in women with preterm uterine contraction can help identify the pregnancies at risk and to select proper management protocol.