Garment sector is one of the industrial sectors in Ethiopia. In this sector the final products are always with defect(s) which reduces attraction from customers and economic benefit from the business. With this intention, quality enhancement of shirt products through defect(s) rejection reduction using SQC tools was a vital task of this research. The study applied Pareto Analysis and Cause-and-effect diagrams for detailed examination of top defects. From the Pareto-analysis six top defect types; cuff assembly seam slip out, sleeve hemming, button slip out, side seam puckering, button missed, and placket seam out have been identified. These defects contributed 81.68% of all defects happening in the case company. Then root-cause analyses for these top defect types have been done and solutions have been suggested to overcome causes to reduce rejected shirts. Finally, the suggested solutions have been practically implemented through the organized implementation team from different departments of the case company including the researcher. This has given remarkable results of almost 67.3%, 2222 shirts, of export rejected shirts have been saved. These saved shirts have been exported additionally to the international market in line with the defect free products of that month and increased the income of the case company by 444,400 ETB to 555,500 ETB per month.