Pine wilt disease caused by pine wood nematode has become the most serious threat to Korean pine ecosystems. However, little is known about the relationships between soil CO₂ efflux and the incidence of pine wilt disease. This study was conducted to measure soil CO₂ efflux rates among damage intensities of pine wilt disease (SLD: slightly damaged; MDD: moderately damaged; SVD: severely damaged) in a natural red pine stand. Soil CO₂ efflux rates were generally lower in SVD than in SLD plots throughout the study period because of decreased root respiration by cutting of infected tree in SVD plots. Mean soil CO₂ efflux rates during the study period were higher for MDD (0.60 g CO₂ m ^-2 h^-1) and SLD (0.54 g CO₂ m ^-2 h^-1) than for SVD (0.47 g CO₂ m ^-2 h^-1) plots. Soil CO₂ efflux rates were positively correlated with soil temperature at the 10 cm depth (r= 0.67, P < 0.001), and soil water content (r = 0.52, P < 0.001), while there was a significant negative correlation between soil CO₂ efflux and soil pH (r = -0.15, P = 0.014). This study suggests that decreased CO₂ efflux in SVD plots compared with SLD could be attributed to reduced root respiration and/or soil environmental changes.