Chemical investigation of ethyl acetate leaf-extract of Pterocarpus santalinoides led to isolation of a friedelane-terpenoid. Structure elucidation was done by comparison of the Nuclear Magnetic Resonance (NMR) spectral features with literature data and was consistent with reported values for friedelan-3-one. The following microorganisms (Clinical isolates): methicillin resistant Staphylococcus aureus (MRSA), S. aureus, Corynebacterium ulcerans, Streptococcus pneumoniae, Campylobacter jejuni, Helicobacter pylori, Escherichia coli, Shigella dysenteriae, Candida tropicalis and Candida krusei were used for the in vitro antimicrobial activity. The isolated compound had Minimum Inhibition Concentration (MIC) value of 10 μg/ml for MRSA, H. pylori, E. coli and Minimum Bactericidal/Fungicidal Concentration (MBC/MFC) of 40 μg/ml for E. coli; 20 μg/ml for MRSA, H. pylori and C. krusei; 10 μg/ml for S. aureus, S. pneumonia and C. tropicalis. It showed moderate antimicrobial activity against most of the pathogens tested. This is also the first report of the isolation of friedelan-3-one from this species.Key words: Friedelan-3-one, methicillin resistant Staphylococcus aureus (MRSA), Helicobacter pylori, Escherichia coli.