This paper describes the results of using oxygen (O2) plasma to treat both greige and scoured cotton yarns to cause significant degradation of cellulose. This study is an effort to reduce hazardous caustic chemicals commonly used to make the cellulose molecule more accessible for uses in such applications as biofuels. Through high power density, 0.46 W/cm2, and the study of varying exposure times, we find longer durations of 30 min to 90 min result in significant cellulose structure degradation. Due to waxes and contaminants found on greige yarns, scoured yarn degradation occurs at shorter exposure times than greige yarns, however, both experience tearing and pitting with longer exposures. This study provides evidence that significant degradation of cellulosic yarns can be achieved through high power density O2 plasma exposure.