Mature-green tomatoes (Lycopersicon esculentum M. cv. Sakata TVR) were stored at 5, 10, 15, 20, 25, 30, 35, or 40C. During storage, the respiration rate and C2H4 production were suppressed at 5, 10, and 35C. Tomato ripening and ethylene production were suppressed and injury was obvious at 40C. Mitochondrial oxidation of malate, succinate, α-ketoglutarate, and citrate were significantly suppressed at 30 and 35C. The respiratory control ratios and ADP:O ratios of 35C were consistently lower than those at 25C. Tomato mitochondria developed the cyanide-insensitive pathway of respiration with increased storage temperature, especially at 30 and 35C, and with extended storage time. The NAD+ -dependent malic enzyme increased at 35C, but malate dehydrogenase activity did not increase with ripening at 35C.