Amides in a CH2CI2 extract from the fruits of Piper retrofractum were detected by HPLC/APCI-MS. Seven new unsaturated amides, together with six known ones, were isolated, and their structures were determined to be N-isobutyl-2E,4E,12Z-octadecatrienamide (1), N-isobutyl-2E,4E,14Z-eicosatrienamide (2), 1-( octadeca-2E,4E, 12Z-trienoyl)piperidine (3), 1-( eicosa-2E,4E, 14Z-trienoyl)piperidine (4), 1-( octadeca-2E,4E-dienoyl)piperidine (5), 1-(eicosa-2E,4E-dienoyl)piperidine (6), and 1-(eicosa-2E,14Zdienoyl)piperidine (7) on the basis of chemical and spectroscopic evidence.