ABSTRACT Antimicrobial Activity of Lecythophora sp. strain 30.5, Endophytic Fungi Extract from Alyxia reinwardtii BL Some endophytic fungi isolated from Alyxia reinwardtii BL (Pulasari), one of these fungi identified as Lecythophora sp. strain 30.5. This endophytic fungi was cultivated and extracted its component substances with ethyl acetat, n-heksan, and n- butanol. The extracts of Lecythophora sp. strain 30.5 was evaluated for antimicrobial activity and determine Minimum Inhibitory Concentration (MIC) by using agar dilution method. Varying concentration of the extracts (between 1,2 x 102 ppm and 5,0 x 103 ppm) were prepared and 0,50 µL suspense of each test microorganism was spotted on the surface of the solidified extract-agar mixture, then incubated 37 ºC for 24-48 hours. The organism used in this study were Staphylococcus aureus ATCC 25923 dan Bacillus subtilis FNCC 0059 for Gram positive bacteria, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, dan Salmonella typhi for Gram negative bacteria, and Candida albicans for yeast. The ethyl acetat extract showed no antifungi activity and the MIC of this extract was 3,0 x 103 ppm against all the bacterial strains. The MIC of n-heksan and n-butanol extract were 5,0 x 103 ppm against Candida albicans, but had no antibacterial activity. Key words : endophytic fungi, Alyxia reinwardtii BL (Pulasari), Lecythophora sp. strain 30.5, antimicrobial activity, Minimum Inhibitory Concentration, agar dilution.