Air permeability is often used in evaluating and comparing the obreathabilityo of various fabrics for end uses such as raincoats, tents, and uniform shirtings. This paper focuses on the optimization of yarn and fabric factors affecting the air permeability of knitted fabrics. For this purpose, the Taguchi experimental design technique, analysis of variance (ANOVA), and signal-to-noise (S/N) ratio were used. Instead of 27 different fabric configurations, with respect to full factorial design, only nine fabric configurations with respect to Taguchi's L9 orthogonal design were knitted and tested. As a result of these experiments, the fabric configuration satisfying the maximum air permeability value was determined, which showed considerable improvement in the S/N ratio as compared with the initial design.