Two novel diterpenoids, thecacorins A (1) and B (2), were isolated from Thecacoris batesii and their structures were established as ent-3β,20-epoxy-16-kaurene-3αα,12β-diol and ent-15-beyerene-2β,3β-diol, respectively, on the basis of extensive spectroscopic analysis, especially, 1D NMR spectra, in conjunction with 2D experiments, COSY, NOESY, HMQC and HMBC