This study was carried out to investigate the major flavonoid of Leptadenia pyrotechnica and to evaluate the antimicrobial activity of stem fractions. The flavonoids were extracted with ethanol and the crude extract was purified by thin layer chromatography where a flavonoid (compound I) was isolated. The structure of this compound has been partially characterized by its UV and ¹HNMR spectra. Different fractions of Leptadenia pyrotechnica stem were assessed for antimicrobial activity against: Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Candida albicans. However, all fractions failed to show inhibitory effect on all test organisms.