Diepoxyrollin (1) and diepomuricanin B (2), two new Annonaceous acetogenins were isolated from the cytotoxic MeOH extract of the seeds of Colombian Rollinia membranacea. Five others known acetogenins were also isolated, dieporeticanin 1, dieporeticanin 2, diepomuricanin A, rollinone, and sylvaticin. Their structures were elucidated on the basis of spectral data. Compounds 1 and 2 belong to the rare type of diepoxyacetogenins, which are probably precursors of the mono-tetrahydrofuran acetogenins.