To convert cotton fibers into yarn, a considerable number of machines are required. Each and every machine has different parameters, which can be changed to optimize the characteristics of intermediate or final products. Apron spacer size and top roller pressure are considered as some of the major factors that determine the characteristics of the yarn. To properly draft the material adequate contact of top and bottom rollers and proper apron spacing are necessary. In this thesis work the effect of five different spacer sizes i.e. 3.0mm, 3.25mm, 3.5mm, 3.75mm and 4.0mm by varying the top roller pressure of 2.1bar, 2.2bar and 2.3bar on 100% cotton of 20Ne ring spun yarn has been investigated. The change in cotton yarn properties like irregularity percentage, imperfection level, and tensile strength has also been reported. The process parameters from blow room up to ring spinning are kept identical. The result shows that at closer apron spacer, higher pressure generally improves the irregularity percentage, imperfection level, and tenacity of the yarn. But at wider apron spacer increasing the pressure has an opposite effect on the yarn. The optimum yarn quality has been obtained at top roller pressure of 2.3bar and at spacer size of 3.5mm.