Disclosed herein is a method and associated monitoring system for monitoring the tension of a pile yarn in a tufting machine which is provided with several tufting needles and assumes cyclically successive machine positions during various machine cycles, where this pile yarn (3) is incorporated in a fabric in the machine cycles by means of a tufting needle which is positioned in various needle positions at a respective distance from the fabric (7) by positioning the tufting machine in the machine positions during each machine cycle. The method includes generating measurement signals (D.sub.v) by means of a motion sensor which are an indication of the pile yarn consumption of this pile yarn, determining machine position data (D.sub.m) which are an indication of one or more machine positions per machine cycle and evaluating the measurement signals (D.sub.v) on the basis of the machine position data (D.sub.m).