The effects of soman on the resting contractile tension of human uterine arteries, and on contractions of these arteries to vasoactive agents were investigated. 2. Soman did not alter the resting tension of helically-cut strips of human uterine arteries. 3. Soman did not alter concentration-response curves of the strips to noradrenaline, serotonin, potassium chloride or histamine. 4. Soman increased contractile tension of human uterine artery strips to subsequently added 1 microM noradrenaline. 5. It is possible that this enhancement may be involved in decreased regional blood flow following soman administration.