The fermentation, isolation and structure determination of ravidomycin analogs FE35A and FE35B are reported.They were isolated from S. rochei 3218-GM2, which was isolated from a soil sample collected in Iou-island, Tokyo.FE35A and FE35B exhibited cytotoxicity against U937 leukemia cells with IC50 values of 3.7 and 4.6 nM, resp.Both compounds induced a caspase-3 like activity in U937 cells at concentrations >200 nM for 3 h after administration.