Postharvest fungal decays of tomato caused by Alternaria alternata, Botrytis cinerea, Geotrichum candidum and Rhizopus stolonifer, result in significant economic losses during different stages from harvesting from farm to fork. The efficacy of ozone gas for controlling fungal postharvest fungal decays of tomato was evaluated. In the laboratory tests, Ozone 0.1 ppm in the atmosphere above inoculated PDA didn't affect radial growth, fresh weight or dry weight of the previously mentioned fungi, but, the development of aerial mycelium over the cultures appeared to be blocked. On the other hand, ozone significantly decreased the spore germination of the most tested fungi.  Ozone also, decreased the density of fungal spores in the air of a storage room when it was applied for 24 hours. In fruit tests, ozone 0.15 ppm at 10 °C and RH 99% prevented the development of lesions on wound-inoculated tomato fruits for 7 days. After 10 days, progressive lesions were observed but were smaller than those on control fruit. In contrast, when the treatment was applied at 22°C, lesions developed similarly to those on control fruit but sporulation was inhibited. There was no evidence of phytotoxicity associated with these ozone treatments.