The main aim of this study is to investigate the effect of modified atmosphere (MA) on the quality of squash during storage. Squash fruits were stored at three levels of O2 concentrations (1, 3 and 5%), three levels of CO2 concentrations (2, 6 and 10%) under cold storage at 10 °C and 70 % relative humidity as compared with storage in normal air (22C and 70%RH) in perforated and non-perforated packages. CO2, O2 and ethylene inside the packages were recorded. Also, weight loss, hardness and color of fruits were determined. The obtained results indicated that, the concentration CO2 inside the package of fresh squash during storage ranged from 4.71 to 24.02 % for all treatment. The CO2 and ethylene concentrations inside the package increases with increasing CO2 and O2 levels during storage, while, O2 concentrations inside the package decreases with increasing CO2 and O2 levels during storage. The accumulated weight loss of squash increased from 0 to 2.17, 0 to 2.48 and 0 to 2.80 %, when the storage period increased from 0 to 14 days at 1, 3 and 5% O2 levels, respectively compared to 35% for normal air (traditional storage). The squash hardness slightly decreased with storage time, the MA storage had slight effect on the hardness. Package perforation obtained a good results in terms of weight loss compared to the traditional storage. The colour (L*) of squash decreases with increasing CO2 level during storage period.