Citrus fruits are among the most important fruit in world. Postharvest decay of orange is main restriction in delivery at marketing. The aim of current study was to investigate the antifungal activity of Carum copticum and Eucalyptus australiana essential oil on orange postharvest decay fungi. The effects of essential oils on radial growth of some of the most common pathogenic Fungi (P. digitatum, P. italicum and A. alternata) were determined by in vitro and in vivo study. Both essential oil affected radial growth and fruit infection. All essential oils concentration significantly decreased fungi growth and in 3000 ppm of ammi the inhibitory effect was 99%. It is concluded that the essential oils could be successfully controlled postharvest pathogenic and although they controlled fruit decay but more experiment needs to alleviate their effects on fruit and evaluate their effects on fruit taste.