Acrylic resin heat cure is a material that commonly used by dentist in making denture base. However, acrylic resin has a weakness that is porosity and roughness surface. Porosity roughness surface facilitate the accumulation of food debris and microorganism, like Staphylococcus aureus, which can cause denture stomatitis. Denture stomatitis can be prevented by the immersion of denture with antibacterial material, such as black seed and betel leaf. Black seed contain thymoquinone; thymohydroquinone; tannin and betel leaf contain kavikol; phenol; seskuiterpan; and flavonoid. Research purpose : To know the differences of antibacterial inhibition potency between black seed extract and betel leaf extract against the growth of Staphylococcus aureus on acrylic resin denture base. Research method : The type of research used was laboratory experimental research. 27 acrylic resin base used as a sample. Acrylic resin base divided into 3 groups: (1) Acrylic resin base immersed in black seed extract solution with 0,5% concentration, (2) Acrylic resin base immersed in betel leaf extract solution with 25% concentration (3) Acrylic resin base immersed in aquades as a negative control. Immersion is done for 8 hours in room temperature. The collected data will be analyzed using Mann-Whitney test. Research result : The average growth of bacteria in, black seed solution 0,5% is 3,11; betel leaf solution 25% is 1.00; and aquades solution is 6.00. The result of Mann-Whitney test on black seed extract and betel leaf extract, p=0,135 more than 0,05 (p>0,05) that shows there is no difference between group of betel leaf and group of black seed in inhibit Staphylococcus aureus. Conclusion : The conclusion of this study is no meaningful difference between black seed extract group and betel leaf extract group in inhibit the growth of bacteria