BACKGROUND: Difficult tracheal intubation during anesthetic induction can be a lifethreatening situation, especially in pregnant women. This is the leading cause of anesthetic related maternal mortality. The ability to predict such cases preoperatively would be of great value. We conducted a prospective study to investigate the incidence of difficult intubation and the usefulness of various predictive factors for difficult intubation in pregnant women. Metoods: Predictive studies on three hundred nine pregnant women who underwent general anesthesia and tracheal intubation for an elective caesarean section were conducted using airway measurements such as a modified Mallampati classification (m-MP), interincisor gap (IG), thyromental distance (TMD), and sternomental distance (SMD). Then direct laryngoscopic gradings (LG) and difficult intubation (DI) were determined. All patients were evaluated on the basis of these studies, and the sensitivity, specificity, positive and negative predictive values (PPV, NPV) of each study were calculated. RESULTS: DI was observed in 5 patients (1.62%) and failed intubtion was observed in 1 patient (0.32%). The sensitivity and specificity of the m-MP were 80% and 82% respectively, and those of the IG were 80% and 77% respectively. A combination of the m-MP and IG resulted in high sensitivity and specificity (100% and 76% respectively), but low PPV (5%). CONCLUSIONS: This study concluded that m-MP and IG were the most sensitive and specific tests when used alone or in combination.