Mulberry silk can be deemed as the most important silk fiber due to its cultivability. In addition to this, its fiber properties make it one of the most important natural fibers and textile raw materials. Silk fibers which can not be reeled continuously are counted as silk waste and they are used as short staples in industry. Moreover, filament silk can be converted to staple silk fibers, in order to use in blended yarn productions. In this study, we blended mulberry silk and combed cotton fibers in draw-frame and used them to produce silk/cotton blended yarns with three different silk/cotton blending ratios and with three different twist coefficients in ring and siro spinning systems. We performed tests such as unevenness, strength and hairiness to determine physical properties of these yarns. In conclusion, we have found siro spinning system more efficient than ring spinning system due to physical properties of spun yarns and it was clear with our results that tensile strength, unevenness and hairiness values have increased with silk content increment in silk/cotton blended yarns.