It is well know that the wax content of cotton plays an important role in the processing efficiency of its conversion from fiber to fabric and in the subsequent ease of its wet processing (dying and finishing). It is also believed that wax content may play an important role in the strength and elongation of yarns spun from these cottons. In this study, 36 varieties of US upland cotton were chosen and the effect of cotton wax on fiber-to-fiber cohesion and yarn properties was investigated.