In vivo sister chromatid exchange (SCE) induction by vinyl and allyl carbamates was examined in alveolar macrophage, bone marrow, and regenerating liver cells of C57BL/6J x DBA/2J F1 mice. Allyl carbamate was effective in producing increases in SCE frequencies (relative to base-line SCE) over a dose range of 220 mumol/kg (approximately 2 times base line) to 2.2 mmol/kg (3 times base line). In general, alveolar macrophage and regenerating liver cells had higher responses, although not significantly, than did bone marrow. Vinyl carbamate produced significant increases in SCE frequencies over a dose range of 10 mumol/kg (2 times base line) to 75 mumol/kg (8 to 10 times base line). At the highest dose, SCE frequencies in extrahepatic tissues of hepatectomized mice were significantly higher than in intact mice and, within hepatectomized mice, alveolar macrophage and regenerating liver cell responses were greater than were bone marrow responses. Vinyl carbamate was approximately 30 times as potent a SCE inducer than we reported previously for ethyl carbamate. To date, our studies of six different carbamate esters have indicated a striking similarity in relative potencies for SCE induction and their known tumorigenic potencies.U