Bioactivity-guided fractionation led to the isolation of two new Annonaceous acetogenins, annocatacin A ( 1). and annocatacin B ( 2). from the seeds and the leaves, respectively, of Annona muricata. Compounds 1 and 2 are the first examples where the adjacent bis-tetrahydrofuran ring system is located at C-15. The new structures were elucidated and characterized by spectral and chemical methods. Both Annonaceous acetogenins 1 and 2 showed significant in vitro cytotoxicity toward the human hepatoma cell lines, Hep G2 and 2,2,15, and were compared with the known adjacent bis-tetrahydrofuran acetogenins, neoannonin ( 3). desacetyluvaricin ( 4). bullatacin ( 5). asimicin ( 6). annoglaucin ( 7). squamocin ( 8). and rollimusin ( 9).