Two novel labdane diterpenoids, 15ξ-methoxy-labdan-8(17),11(E),13(14)-trien-15,16-olide (1) and 12(S)-hydroxy-15ξ-methoxy-labdan-8(17),13(14)-dien-15,16-olide (2) were isolated from the rhizomes of Aframomum sceptrum K. Schum (Zingiberaceae). Their structures were established on the basis of their spectroscopic data. Stigmast-4-en-6β-ol-3-one and caryophylene oxide were also obtained. In vitro trypanocidal and leishmanicidal activities of labdanes 1 and 2 were evaluated. Compound 2 exhibited activity similar to that of reference drugs against Leishmania donovani.