Marine microorganisms continue to be a productive focus for much of marine natural products investigation.1–3 These organisms flourishing in diverse marine environments, have produced a wide variety of structurally unique and biologically active secondary metabolites many of which have attracted considerable attention.1,4 In the last decades, the number of reported secondary metabolites from marine bacteria has steadily increased.2 Medium ring-sized peptides containing the amino acids leucine, isoleucine, phenylalanine, valine and proline have been reported from diverse marine sources, including microorganisms.5,6 The genus Bacillus has produced biologically active compounds.7,8 In our search for bioactive natural products from the bacterium B. amyloliquefaciens collected from South China Sea deep-sea sediment, the culture broth contained two new cyclic tetrapeptides, cyclo-(Leu-Pro-Ile-Pro) (1) and cyclo- (Tyr-Pro-Phe-Gly) (2) (Figure 1).