Some species of the Cunoniaceae are reputed to possess medicinal properties. An investigation of 50 species of this family in New Caledonia has permitted the screening of 204 extracts (101 ethyl acetate extracts and 103 methanol extracts) for antimicrobial activities against one yeast (Candida albicans), one filamentous fungus (Fusarium oxysporum), and eight bacterial species (Erwinia carotovora, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Corynebacterium accolans, Bacillus subtilis).Ninety-six per cent of the plants exhibited antimicrobial activity, with a significant difference in the number of responses between fungi (18.8%) and bacteria (81.2%). Moreover, Gram +ve strains appear more sensitive than Gram -ve ones. The most active plants were Acsmithia meridionalis, A. pedunculata, Cunonia macrophylla, C. vieillardii, Pancheria alaternoides, and P. elegans. Cunonia macrophylla appears to be the best candidate for a chemical investigation using bioguided fractionation as extracts from its leaves and flowers effectively inhibited six strains (one yeast, two Gram -ve bacteria and three Gram +ve bacteria).