The production of volatile sulfur compounds in modified atmosphere of packaged broccoli was investigated. Broccoli heads were sealed in 0.03-mm-thick low density polyethylene film and held at 10, 20 or 30℃ for 72 h. Nonpackaged heads were also stored at the same temperatures. In the package held at 30℃, O₂ and CO₂ concentrations were less than 1% and more than 19%, respectively, and methanethiol was detected within 6 h. In the package held at 20℃, O₂ and CO₂ concentrations were less than 0.4% and more than 17%, respectively, and methanethiol was detected within 18 h. The percentage of electrolyte leakage from packaged broccoli held at 20℃ and 30℃ increased to a greater extent than that of nonpackaged broccoli during storage. However, storing the packaged broccoli at 10℃ created a favorable modified atmosphere condition of around 3% O₂ and 10% CO₂ inside the package. In this condition volatile sulfur compounds were not detected and no significant change was observed in percentage of electrolyte leakage. At all temperatures, total chlorophyll contents were higher in packaged broccoli than in nonpackaged broccoli. These results indicate that, volatile sulfur compounds such as methanethiol were formed when the atmosphere inside the package had extremely low O₂ and high CO₂ even if broccoli was green and the visual quality had not deteriorated.