A novel alkaloid, maingayinine, together with dicentrinone, dicentrinene, L-2-O-methyl-chiro-inositol, allantoin, glaucine, N-phenyl-2-naphthylamine, terephthalic acid and ayanin, was isolated from the twigs of Mitrephora maingayi Hook (Annonaceae). Their structures were established predominantly by IR, MS and NMR spectral data.