Peanut (Arachis hypogaea) is a crop that can produce resveratrol, a compound with various biological properties, such as those that exert antioxidant, anticancer, and anti-inflammatory effects. In this study, trans-resveratrol was detected in the roots, leaves, and stems of tan and purple seed coat peanuts (Arachis hypogaea) cultivated in a growth chamber. Both cultivars showed higher levels of resveratrol in the roots than the other plant parts. Thus, both cultivars were inoculated with Agrobacterium rhizogenes, in vitro, to promote hairy root development, thereby producing enhanced levels of t-resveratrol. After 1 month of culture, hairy roots from the two cultivars showed higher levels of fresh weight than those of seedling roots. Furthermore, both cultivars contained higher t-resveratrol levels than those of their seedling roots (6.88 ± 0.21 mg/g and 28.07 ± 0.46 mg/g, respectively); however, purple seed coat peanut hairy roots contained higher t-resveratrol levels than those of tan seed coat peanut hairy roots, ranging from 70.16 to 166.76 mg/g and from 46.61 to 54.31 mg/g, respectively. The findings of this study indicate that peanut hairy roots could be a good source for t-resveratrol production due to their rapid growth, high biomass, and substantial amount of resveratrol.