Pine wilt disease caused by the pine wood nematode has become a serious threat to Korean pine ecosystems. The objectives of this study were formulated to quantify the impacts of pine wilt disease on carbon (C) and nitrogen (N) dynamics at various levels of damage intensities of pine wilt disease in red pine stands. The study site was located in Jinju City, which is the most severely damaged pine wilt disease area in Korea since the disease outbreak in 1998. Nine plots having various damage intensities of pine wilt disease were established on the same facing slopes and aspects. Litterfall and soil respirations rates were measured for two years (May 2009 and April 2011). The C and N inputs from litterfall decreased with increasing damage intensity from pine wilt disease due to a considerable difference in the stand basal area among the study plots. Mean annual soil respiration rates showed the second-order polynomial relationships with basal area in pine wilt disease stands because of the change in environmental conditions for microbial or root growth activity and organic matter decomposition and/or the decrease in root respiration after removing of the infected trees. These results suggest that C and N cycle in red pine stands are greatly altered by the incidence of pine wilt disease, but these alterations are manifested in different ways by varying degree of damage intensities.