This experiment was conducted to study the effect of postharvest dipping of fresh button mushrooms (Agaricus bisporus) in hydrogen peroxide (H₂O₂) 5% alone or in combination with antibrowning agents (calcium chloride at 3 or 5%, ascorbic acid 3 or 5% and citric acid 2 or 4%) beside dipping in distilled water (control) to inhibition  browning, had the lower level of microbial load and maintaining quality during storage for 12 days at 4 ± 1^oC and 90 ± 2% relative humidity during two successive seasons of 2016 and 1017. Results showed that all studied treatments reduced weight loss percentage, browning index and Polyphenol oxidase activity, total bacteria counts, yeast and mold counts and maintaining of phenolic and flavonoids contents of fresh button mushrooms during cold storage comparing with untreated control. However, dipping button mushrooms in solution H₂O₂ 5% + calcium chloride 5% was the most effective in this concern, which reducing browning, maintaining quality and inhibiting microbial counts for 12 days at 4 ± 1^oC and 90 ± 2% relative humidity.