Fungal pathogens such as Alternaria solani in tomato,Rhizopus stolonifer in strawberry, Botrytis cineara in pepper, Sclerotinia sclerotiorum  in cucumber, and Sclerotium rolfsii in carrot causes many losses of postharvest decay of different fruits affect quality and quantity  during the storage,  marketing and handling. Its control has been and still  largely based on the use fungicides. However, it is able to develop resistance to these chemicals very rapidly, so its control has become problematic.Chitosan (poly-β-(1-4)N-acetyl-d-glucosamine),was applied on maycelial growth of fungi and fruits, by dipping  fruits in solution 0.05% and 0.2% concentrations for five minutes. Invitro, 0.2% Chitosan was the best concentration for inhibition of mycelial growth of postharvest fungi giving 75.7% inhibition of A. solani, followed by 76.9% of R.stolonfer,then 94.9% of S.rolfsii.While, the 0.05% chitosan gave moderate inhibition of A. solani and R. stolonifer and gave high inhibition on S. rofsii, while the two concentrations achived complete inhibition in B. cinerea and S. sclerotiorum. Chitosan treatments applied with acetic acid on fruits gave significant decrease in disease incidence and disease severity.Resultes indicate that chitosan treatments gives good treatmentfor reducing the maycelial growth of fungi and increasing control of postharvest decay of different fruits and roots.