The physiological, physicochemical and microbiological quality of fresh-cut 'Piel de Sapo' melon packaged under 2.5 kPa O-2 + 7 kPa CO2, 21 kPa O-2 and 70 kPa O-2 atmospheres was studied. Initial low O-2 levels combined with moderate CO2 co ncentrations reduced in-package ethylene concentration whereas high O-2 levels avoided anaerobic metabolism. Both 2.5 kPa O-2 + 7 kPa CO2 and 70 kPa O-2 atmospheres significantly reduced the growth of microorgan isms for 14 days of storage at 5 degrees C. Rhodotorida mucilaginosa was initially the dominant yeast, and prevailed during the subsequent storage of fresh-cut 'Piel de Sapo' melon although high O-2 levels as well as low O-2 and high CO2 conditions were found to have a certain inhibitory effect oil its growth. Therefore, a 70 kPa O-2 atmosphere prevented fermentation and significantly improved the quality of fresh-cut melon, while preserving its microbiological stability