To assess Raynaud's phenomenon objectively, thermographic estimation of hands and fingers was performed before and after the disease- and Raynaud's phenomenon-directed therapy in 3 children with mixed connective tissue disease. All the cases were positive in Raynaud's phenomenon, and the surface temperature of their hands and fingers were decreased even before cold challenge. After the cold provocation test at 4 degrees C for 10 sec., the temperature of all or some of the fingers were rapidly decreased, and the recovery of surface temperature of these fingers were markedly delayed. Even after methylprednisolone pulse therapy the pattern of the finger temperature were essentially unchanged, suggesting that steroids are not effective in the treatment of Raynaud's phenomenon. The long-term administration of vitamin-E, oral prostaglandin E1, and/or serotonin-receptor inhibitor were also proved to be not beneficial in improving Raynaud's phenomenon. Thus, thermography is useful in diagnosing Raynaud's phenomenon objectively, in determining the efficacy of anti-Raynaud drugs, and in estimating long-term course of the phenomenon.