This paper presents a method to automatically determine yarn hairiness using Image Processing (IP) techniques. After image acquisition, the samples are analyzed and processed by a custom-made application developed in Lab VIEW from National Instruments with the IMAQ Vision toolkit. The results show that a reliable quantification of the yarn hairiness index can be obtained. This methodology can be used as an efficient alternative to the traditional commercial hairiness testers suppressing their constraints. Step-by-step algorithms used to isolate the yarn core, to highlight the fibres and to measure the hairiness index are described.