This study evaluated the effect of modified atmospheres (MAPs) with low oxygen levels (2.5%) and high carbon dioxide levels (from 5 to 20%) on strawberries. During 12 days of storage at 4°C, various quality and chemical content parameters were evaluated. These including decay, color, weight loss, firmness, total soluble solids, total polyphenols, anthocyanins, and flavonoids, as well as antioxidant capacity and individual phenolic compounds (quercetin, caffeic acid, gallic acid, (-) epicatechin, and p-coumaric acid). Results showed that high CO2 levels had a positive impact on strawberry preservation: weight loss was reduced, anthocyanin content increased, decay and softening were significantly reduced, and vitamin C content was maintained. At the same time, these high concentrations of CO2 did not affect sugar content, color, antioxidant capacity, total phenolic compounds, or total flavonoid compounds of strawberries. A storage time of 12 days at 4°C, under MAP with an initial gas condition of 2.5% O2 + 15% CO2 + 82.5% N2 or 2.5% O2 + 20% CO2 + 77.5% N2, was found to be ideal for preserving the quality of fresh strawberries.