There are 16 species in the genusSaturejaL. (Lamiaceae), of which10are native.This research aimed to investigate the effect of gamma rays and storage conditions and duration on the percentage and components of the essential oil and some biochemical characteristics ofSatureja muticaFisch & C.A. Mey at the Research Institute of Forests and Rangelands.Plants were collectedat the full floweringstageand exposed todifferent doses of gamma rays (0, 2.5, 5, 7.5, and10kGy)at the Atomic EnergyOrganization, Iran.The samples were keptin a refrigerator (4°C)and in the shade(25 ± 2°C) for 0, 120, and 240h. This experiment was performedin acompletely randomizeddesign. Essential oil extraction was done by water distillationfor2h. The composition of their essential oil components was identified usingGC and GC/MS.Somebiochemicaltraits, including phenol content, antioxidant capacity, and carbohydrate content, were measured. The results indicated that irradiation on the percentage of essential oil showeda statistically significant difference. In addition, theinteraction effect of irradiation × storage conditions, irradiation × duration of storage, on the percentage of essential oilwassignificant. According to a comparison of the means, 2.5kGy irradiation produced the highest percentage of essential oil (0.4%); in contrast, a significant decreasewas detectedin components with 7.5 and 10kGy irradiation. It was observed thatthepercentage of some essential oil compounds decreasedwith the gamma-ray intensity increase.2.5kGy of gamma rays and shade storage conditions for 240h led to the highest content of p-cymene and carvacrol. Nevertheless,the highest thymol content wasobtained under refrigeration conditions without irradiation. The maximum phenol content and antioxidant capacity were obtained when the plants were irradiated with 2.5 and7.5kGy gamma rays.However,the maximum carbohydrate ratewas observed in non-irradiated plants.It was concluded that low-intensity gamma rays could improve the percentage of essential oil and main components like p-cymene and carvacrol in S. mutica Fisch & C.A. Mey.