In order to evaluate the effect of Rosemary extract and Thiabendazol fungicide on postharvest rot of Valencia sweet orange, was performed an experiment as factorial arrangement in completely randomized design with four replications. The first factor was storage type including cool (4 °C) and room temperature (25 °C) storages and the second factor was treatment type including unwounded control; wounded control; wounded control inoculated by Penicillium italicum spores; Rosemary extract 150, 300 and 450 mgL-1 ; and Thiabendazol 1.0, 1.5 and 2.0 gL-1. The treated fruits by extract and fungicide were inoculated with Penicillium italicum spores. The fruits were stored in room temperature and cool storage for two months and then the decay percent, TSS, vitamin C and total acid were measured in them. According to the results, the best treatment was Thiabendazol 2.0, 1.5 and 1.0 gL-1 respectively in room temperature storage and Rosemary extract could kept fruit quality in compare with controls.