Abstract: Background and Objectives: Silver ion (Ag+), which added in vitro in the form of silver nitrate (AgNO3) or as silver thiosulfate (STS) complex can act as an effective inhibitor of ethylene action. In addition to inhibiting ethylene action, Ag+promotes indole acetic acid (IAA). The current study was conducted to evaluate the impact of AgNo3 on improvement root formation during micropropagation of Gardenia jasminoides Ellis. Materials and Methods: For multiplication, stem segments were cultured on MS medium supplemented with 0, 3, 5 or 7 mg L–1 benzyl adenine (BA). Elongated shootlets were transferred to different rooting treatments; MS supplemented with naphthalene acetic acid (NAA) or indole butyric acid (IBA) in combination with different concentrations of AgNo3 1, 2 and 3 mg L–1. The antioxidant activity of extracts from each rooting treatment was determined through 2,2-diphenyl-1-picrylhydrazyl(DPPH) radical scavenging activity. Results: Using high concentration of BA (7 mg L–1) led to obtain the highest multiplication rate. Results observed that addition of AgNo3 to medium contained NAA alone doubled the rooting formation percentage. Meanwhile, addition of AgNo3 to MS medium contained IBA alone or both NAA and IBA increased the root formation percentage from 83.33-100%. DPPH radical scavenging activity of different rooting treatments revealed that 2 NAA+2 IBA+2 AgNo3 recorded the highest DPPH percentage (79. 2%). Conclusion: It could be concluded that, the medium supplemented with2 NAA+2 IBA gave the highest number of roots/plantlet. While, the addition of 3 mg L–1 AgNo3 to MS medium supplemented with 2 NAA+2 IBA gave the highest mean length of root/plantlet. Also, it could be concluded that using AgNo3 with 2 mg L–1 NAA+2 mg L–1 IBAA improved the antioxidant capacity of gardenia extracts.