Antifungal and antimicrobial activity of the methanol extracts of three mangrove plant species Aegiceras comiculatum, Avicennia marina and Lumnitzera racemosa has been studied. The specimens have been collected from the Xuan Thuy National Park. The antifungal and antibacterial activity against six human pathogenic microorganisms (Candida albicans, Aspergillus fumigatus, Escherithia coli, Staphyfococcus aureus, Proteus mirabilis and Proteus vulgaris) were determined by agar well diffusion method with analysis of the diameter of inhibition zone. The extracts (10-100mg/ml) of the three mangroves plants species showed promising antimicrobial activity against all tested microorganisms depending upon the natural active components in the extract and their specificity against each microrganism species. The extracts of Aegiceras comiculatum and Avicennia marina strongly inhibited the growth of C. albicans and A. fumigatus. respectively. Lumnitzera racemosa extract showed moderate antibacterial activity against all tested bacteria (E. coli, S. aureus, P. mirabilis and P. vulgaris) which are commonly in urinary tract infections. Further research is needed to determine the chemical components in these plant extracts what is needed for the efficient and sustainable use of Vietnamese mangrove plant species for medical-pharmaceutical purposes.