<jats:title>Abstract</jats:title> <jats:p>Kurahamide, a new dolastatin 13 analog, was isolated from a marine cyanobacterial assemblage, consisting mostly of Lyngbya sp. Its gross structure was elucidated by spectroscopic analysis, and the stereochemistries were assigned based on a chiral HPLC analysis of hydrolysis products. Kurahamide strongly inhibited elastase and chymotrypsin in vitro. In addition, kurahamide moderately inhibited the growth of human cancer cells, including HeLa and HL60 cells.