Velopharyngeal insufficiency(VPI) is a state of inability to make a connected speech by incompetent velopharyngeal port due to various causes. The examination methods are various, but digital subtraction technique is the method of choice because its good quality of image by subtracting surrounding overlapped structures, dynamicity, simplicity and possible quantitative analysis. We examined 102 suspected VPI patients by digital subtraction technique with good results and did quantitative analysis of the results of 28 patients in correlation with the speech evaluation.