Stylopeptide 1 (1) was isolated respectively from the South and Western Pacific Ocean sponges Stylotella sp. and Phakellia costata. Structural determination was accomplished by utilizing highfield (500 MHz) 2D-NMR experiments and confirmed by an X-ray crystal structure determination to provide the assignment cyclo(Pro-Leu-Ile-Phe-Ser-Pro-Ile). The absolute configuration of the new cycloheptapeptide was established by employing results of chiral gas chromatographic analyses.