Two diarylheptanoids, musaitinerins A and B, one heterodimeric phenylphenalenone musaitinerone and four known phenylphenalenones, identified as 4-hydroxy-2-methoxy-9-phenyl-1H-phenalen-1-one, musanolone E, hydroxyanigorufone and irenolone were isolated from the fruits of Musa itinerans Cheesm. Their structures were elucidated using spectroscopic analyses. The antimicrobial activity of these compounds was evaluated against Escherichia coli, Staphylococcus aureus and Candida albicans; the cytotoxic activity of these compounds was also evaluated against human erythromyeloblastoid leukemia (K562) and human alveolar carcinoma epithelial (A549) cell lines, respectively. Musaitinerone and musanolone E exhibited weak effects against the A549 cell line, as compared with adriamycin. However, these two compounds did not exhibit any growth inhibition against K562 cells, S. aureus, E. coli or C. albicans. The other compounds were inactive against all of the tested cell lines and microorganisms, even at concentrations as high as 50 μM.