Respiration rate and ethylene production at high oxygen treatment ($CO_2:O_2:N_2$ ratio=0:30:70 and 0:50:50) in active MA packaging of tomato were relatively greater than air (control) or low oxygen treatment($CO_2:O_2:N_2$ ratio=0:10:90 and 6:2:92). Ethanol production of low oxygen treatment was higher than high oxygen one. Acetaldehyde production was high at low oxygen treatment on the first storage day, but it was sharply decreased compared with high oxygen treatment. The effect of active MA packaging on weight loss, sugar, and ascorbic acid was insignificant. Marketability was maintained for three days in case of high oxygen treatment, and more coloration was accelerated in high oxygen treatment than in low oxygen one.