This experiment was designed to analyze the factors, which are very common in practical sewing, affecting on sewing shrinkage by using orthogonal array ($L_{27}$) table. The results were analyzed by using the computer program, PDP 11/10. The results showed that sewing shrinkage was increased up to 3 times of laundrying but no further changes could be found. Sewing shrinkage was affected much by the number of stitching and yarn tension and the rate increased with proportion to the number of stitching in unit length and yarn tension. When cotton yarn was used in P/C fabrics, the shrinkage was much smaller, but this results did not agree with other articles reported. Sewing by using $sharp$11 needle and 1000$~$1500r.p.m. seemed to lower the shrinkage rate.