This study aimed to assess the effects of different gamma radiation doses from Cobalt -60 isotopic source on seed germination and early growth parameters of Jatropha curcas L. Healthy and dry seeds were subjected to three doses of gamma rays (100, 200 and 300 Gy). The experiment was conducted using randomized complete block design, with three replicates. The significantly maximum germination percentage (89.85 %), seedling survival (92.3 %), seedling collar diameter (0.892 cm), plant height (17.30 cm), number of leaves (7) were observed at 30 days after germination. The results revealed that seed germination percentages and seedling shoot length decreased with increasing dose of gamma-rays. Higher gamma-ray dose (300 Gy) in particular had a pronounced effect on these germination parameters than others, probably because high-dose inhibited cell division due to free radicals and DNA system damage. The LD50 for seeds germination rates was obtained at 254 Gy. These results implied that germination traits of Jatropha curcas seeds were sensitive to increase in gamma-ray.