We report two cases of cellulitis on the saphenous venectomy scar which developed after a coronary artery bypass graft(CABG). A 68-year-old male and a 62-year-old female developed acute cellulitis in the saphenous vein donor extremity after CABG. The repeated bacterial cultures were negative in both cases. However, onychomycosis was confirmed in one patient. The intervals between CABG and the initial bout of cellulitis in the male and female patient were 10 and 22 months, respectively. Although the exact pathogenesis remains obscure, factors such as direct bacterial infection, hypersensitivity to streptococcal exotoxins, a local compromise of lymphatic and venous drainage, and fungal infection might have contributed to the development of cellulitis in these patients. (Korean J Dermatol 1998;36(1) 177-180)