Imazalil and Thiabendazole chemical based fungicides are currently used to control citrus green/blue molds, which is mainly caused by P. digitatum and P. italicum. In order to find alternative methods for control of citrus fruit diseases to avoid fungicide caused health and environmental problems, current research was conducted to explore the antifungal effectiveness of H 2 O 2 -Ag + (Hydrogen peroxide stabilized with silver ions), which is a universally applicable and high effective disinfectant against pathogenic microorganisms, and has been used to control postharvest decay of fresh fruits in most developed countries, in the context of in vitro and in vivo P. digitatum and P. italicum development in the Newhall navel orange. H 2 O 2 -Ag + was found to be effective in inhibiting in vitro radial growth and in vivo inoculated lesion development of Penicillum italicum and Penicillum digitatum. Dipping fruit with H 2 O 2 at concentrations of 1-2% before storage reduced the decay incidence of orange after 30 and 60 days cold storage following by 3 days shelf life, although it was less effective than the positive control of fungicide Imazalil (500ppm). H 2 O 2 provided a disinfectant effect on the pericarp, as indicated by significant reduction of total bacterial, mold and yeast counts. After cold storage and shelf-life, no significant difference was found among all treatments in the total soluble solids (TSS), titratable acid (TA), while higher vitamin C content was found in the Imazalil treated fruit. This research suggest that H 2 O 2 can be an alternative to chemical fungicides that, although more effective, pose problems due to their residue levels and health concerns, especially for the organic fruit industry.