Two polyesters of a new β-dihydroagarofuran sesquiterpene pentaol were isolated from the seed oil of Celastrus angulatus. Their structures were elucidated mainly on the basis of 1D and 2D NMR spectrometry. The plant Celastrus angulatus is a traditional insecticide and is widespread in China [1]. Previous investigations of the biologically active constituents of this plant led to the isolation of a few insect antifeedant compounds from the root bark [2,3]. These were found to be the polyesters of a β-dihydroagarofuran sesquiterpene polyol. We have now found that the seed oil of this plant also contains these kinds of compounds, including both alkaloids and non-alkaloids possessing 1,2,8,9,13-pentahydroxy, 1,2,8,9-tetrahydroxy, 1,8,9,13-tetrahydroxy, and 1,2,8,9-tetrahydroxy-β-dihydroagarofuran parents. This paper reports on the structures of two 1,2,8,9,13-pentaesterified β-dihydroagarofuran compounds (3 and 4). Baxter and coworkers have already reported a few polyesters of the 1α,2β,8α,9α,13-pentahydroxy-β-dihydroagarofuran skeleton (1) [4]. The ones we report here, however, are derivatives of a 1β,2β,8α,9β,13-pentahydroxy-β-dihydroagarofuran (2), and hence differ from those based on 1 in the stereochemistry at C-8 and C-9. No other derivatives of 2 have been identified in Celastraceae specimens.