THIS PAPER PRESENTS A FEASIBILITY STUDY ON AN INNOVATIVE CONCEPT FOR ON-LINE DIMENSIONAL INSPECTION USING ACOUSTIC FREQUENCY SPECTRUM. THE PRINCIPLE OF THIS CONCEPT IS BASED UPON THE RESONANT FREQUENCIES OF AN ELASTIC PART DEPENDING UPON THE MASS AND STIFFNESS DISTRIBUTION OF THE PART. AS THE PHYSICAL DIMENSIONS CHANGED DURING THE MANUFACTURING PROCESS, THE MASS AND STIFFNESS OF THE PART ARE ALTERED. THE ACOUSTIC SPECTRUM OF THE PART CAN BE USED TO DETECT THE CHANGES OF THE RESONANT FREQUENCIES AND, CONSEQUENTLY, THE DIMENSIONAL DEFECTS CAN BE IDENTIFIED. THREE TEST CASES ARE PERFORMED AND CONCLUSIVE RESULTS ARE FOUND.