Rusmarin's leaf ( Rosmarinus officinalis L. ) is one of the traditional medicines that can be used for mosquito repellant. anti-microbes, carminativa. diuretic, and low blood pressure. The purpose of this research is to investigate the activity of biolarvicide, anti-microbes, and toxicity of rusmarin leaf's extract. Rusmarin's extract was formed by multistage maceration method using n-hexane solvent. ethyl acetate, and methanol. The next stages were phytochemical nitration. biolarvicide test, anti-microbes test with jelly diffusion method, and toxicity test using BSLT for all extracts, following results were found for phytocheirical nitration:n-hexane extract contains steroid/triterpenoid, aetheric oil. and coumarin; ethyl acetate extract contains alkaloid, flavonoid, saponin, steroid/triterpenoid, and coumarin; methanol extract contains flavoncid, saponin, tannin, steroid/triterpenoid, and coumarin. As for biolarvicide test, most active extract is /7-hexane extract with LC50 33.30 ppm. followed by ethyl acetate extract with LC > 122.20 ppm. and methanol extract with LC50, 126.01 ppm. Anti-microbes test was done using paper disc diffusion method, the inhibition zone were found to be 0.06 °/o. 0,15 %. 0,29% towards Escherichia coli bacteria for n-hexane extract, ethyl acetate, and methanol. Well method was used for Slaphylo coccus and Candida albicans with lowest inhibition zone ol 25%, wlule ethyl acetate doesn 't have any activity. The results for toxicity test using BSLT method are: n-hexane extract LC50 I 85,74ppm, ethyl acetate extract LC50 51 ,33ppm. lastly methanol extract LC%03 I ,46 ppm. From the result , we can conclude that n-hexane extract have the highest anti-microbes activities with lowest toxicity, while methanol extract resulting in lowest anti-microbes activities but with highest toxicity. Additionally. Candida albicans activity was not found in ethyl acetate extract.