Introduction: To date, the Bishop score remains as the standard method to predict the successfulness of labour induction. Possible role of transvaginal ultrasound measurement of cervical length provides conflicting evidences. This study compares the value of transvaginal ultrasound cervical length (TVSCL) and the Bishop score (BS), in predicting the success of labour induction in nulliparous pregnancy beyond 40 weeks with unfavourable cervix. Method: In this prospective cohort study pre induction TVSCL and Bishop score were measured in 392 nulliparous women who underwent induction with vaginal Prostaglandin (PGE2) at 40 weeks+6 days. Achieving a cervical dilation of 8cm was considered as a successful induction. Predictive value of TVSCL and BS, in determining successful induction, and amniotomy to successful induction time interval (TI) were analyzed using chi-square test, unpaired t-test, multiple logistic regression, Pearson’s co-efficient and receiver-operating characteristics (ROC) curves. Results: Induction of labour was successful in 75.5% (n=296) of the women. There was a significant difference in mean TVSCL, between successful and failed induction groups (P=0.02). Best cut-off value of TVSCL for predicting successful induction was 3.3cm. However TVSCL failed to demonstrate significant discriminatory value (Area under the ROC curve (AUC)= 0.545;95% CI,0.496-0.597;P=0.17). Meanwhile the AUC for the Bishop score >3 was significant (AUC=0.548;95%CI,0.548-0.647;P=0.006). However, sensitivity and specificity of the Bishop score in predicting induction success were 76.0% and 44.8% respectively. There was no significant association between TVSCL and TI (R=0.02, P=0.06). Conclusion: TVSCL is not an accurate predictor for the outcome of labour induction in nulliparous pregnancy beyond 40 weeks with unfavourable cervix. Nevertheless, the Bishop score appears to be of poor predictive value.