Test methods for quality control should relate to reference methods which can be calibrated independently of the cotton which is the material to be measured. Thus, longterm continuity and comparability can be guaranteed. One should always separate values of bundle strength from average values of single fibre strength. Up to now the bundle strength is the characteristic value for the cotton technology. As the determination of the bundle strength is strongly biased by the test procedure - the modern HVI systems included - it should be tried to formulate a simple reference method considering also the fact that the strength of cotton fibres depends on the length class of the fibres. Therefore a reference method was developed on the basis of traditional bundle testing using a universal tensile tester.