Twenty erythema nodosum leprosum (ENL) patients were examined. Coagulation studies were carried out in 13 of them during their active stage and 7 in the latent stage. From these 13 patients, 6 were re-examined when the disease became latent. From these observations a conclusion can be drawn that there are coagulation abnormalities in the majority of ENL patients in the active stage and these abnormalities will return to normal values when the disease becomes latent.