A new angiogenesis inhibitor, FR-118487 was obtained by chemical modification of FR-111142 which was isolated from the fermentation products of Scolecobasidium arenarium F-2015. The antiangiogenic activity of FR-118487 was compared with that of the parent compound, FR-111142. In the endothelial cell proliferation test in vitro and the angiogenesis in the chick embryo chorioal-lantoic membrane assay, FR-118487 had about 5∼10 times stronger antiangiogenic activities than FR-111142. In addition, FR-118487 inhibited the angiogenesis in the rabbit corneal assay and suppressed the solid tumor growth in mice. These findings showed that FR-118487 would be a unique antiangiogenic agent with promising antitumor activity.