Objective: Noninvasive diagnostic methods do not supply sufficient data for patients with left bundle branch block (LBBB) accompanied with coronary artery diseases (CAD). Therefore, generally coronary angiography is required for these patients. Our aim was to evaluate the diagnostic value of multislice spiral computed tomographic (MSCT) coronary angiography to detect CAD in patients with LBBB. Methods: Sixty one patients (31 males, 30 females, mean age: 56±13 years) with LBBB who have determined stenosis higher than 50% in quantitative coronary angiography were included in the cross-sectional study. The MSCT coronary angiography was applied to the patients with a 16-detector MSCT scanner that has an electrocardiographic synchronization unit. Each coronary artery was evaluated segmentally in the images acquired from MSCT coronary angiographies and any detected stenosis higher than 50% was recorded. Results: The data of 793 coronary artery segments achieved from MSCT coronary angiographies of 61 patients (13 segments for each patient) were compared with the results of conventional coronary angiographies of the same patients. When all the segments evaluated were included in this comparison, the diagnostic accuracy, sensitivity, specificity, positive and negative predictive values of MSCT coronary angiography to detect stenosis higher than 50% were 91%, 67%, 97%, 85% and 92%, respectively. Also, it was observed that, MSCT coronary angiography has 80% sensitivity and 90% specificity to detect, at least, one segment coronary artery stenosis. Conclusion: The MSCT coronary angiography can be utilized as a noninvasive diagnostic method for patients with LBBB, in order to evaluate coronary artery disease.