Post-harvest losses particularly due to fungal invasions, is a major factor in limiting the shelf life of many fruits and vegetables. In order to study the effects of essential oils of thyme (Thymus kotschyanus), basil (Ocimum basilicum) and rosemary (Rosmarinus officinalis) on control of grey mold (Botrytis cinerea) disease in pear, a series of in vitro and in vivo (during cold storage of pear fruits) experiments was conducted. The concentration of essential oils used were 0 (control), 100, 200, 300, 400 and 500 ?l/l of PDA and 0 (control), 100, 300 and 500 ?l/l for in vitro and in vivo experiments, respectively. The results of in vitro experiment showed that rosemary and thyme oils had the lowest and the highest inhibitory effects on the fungal growth. Rosemary oil had no inhibitory effect on the fungal growth even at 500 ?l/l of PDA, but thyme oil, at concentrations above 200 ?l/l of PDA, completely inhibited the fungal growth. The results of in vivo (cold storage of fruits) experiment showed that essential oil treatment had significant inhibiting effects on fungal growth. The number of infected fruits and disease severity were reduced in the treated fruits. With increase in the essential oil concentration, fungal growth was further reduced. The highest vs the lowest number of infected fruits and disease severity were observed in 0 (control) vs 500 ?l/l of essential oil treatment, respectively. Also the results of this study revealed that thyme and rosemary essential oils had the highest and the lowest reducing effects on the number of infected fruits and on grey mold severity, respectively.