Streptococcus mutans bacterial infection can cause tooth damage such as caries or cavities which can disturb comfort. The activity of S. mutans bacteria can be controlled with ingredients that contain antibacterial substances. The aim of this research is to determine the inhibitory power of a combination of compounds contained in the endophytic bacteria Pseudomonas azotoformans UICC B-91 and Ruta angustifolia leaves as an antibacterial for S. mutans. This research using disc diffusion inhibition method with 7 types of test formulations, namely a combination of P. azotoformans UICC B-91 and R. angustifolia extracts (1:1, 1:2, 2:1), P. azotoformans UICC B- 91 extract, R. angustifolia extract, positive and negative control. The result shows that all formulations are proven to produce an inhibitory zone against S. mutans bacteria. The combined formulation with a ratio of 1:1 produces an average inhibition zone of 7.5 mm, the 1:2 combination has an average inhibition zone of 7.75 mm and the 2:1 combination has an average inhibition zone of 10.09 mm. The best results in inhibiting the growth of S. mutans bacteria were in the combined formulation of P. azotoformans and R. angustifolia 2:1, which produced an average inhibition zone of 10.09 mm in the "strong" category.