Tarn neppiness, one of the most important aspects of cotton. yarn quality, has significant influences on the downstream processes; therefore it should be well controlled. In this study, in order to examine the changes in nep count during the production of yarn, cotton materials from different origins have been investigated at some parts of the production line of carded yarn. Moreover to predict of the yarn nep count from fibre properties measured by HVI and AFIS instruments, the regression equations were obtained by means of multiple regression analysis. In order to see the validity of each equation, the correlations between the measured and estimated yarn nep counts were obtained.