Chromatographic investigation of an acetone extract of the octocoral Xenia florida afforded three new xenicane diterpenes, namely, florxenilide A (1), florxenilide B (2), and florxenilide C (3), in addition to seven known xenicane diterpenes and two known cadinene sesquiterpenes. Structures were elucidated through spectroscopic analysis, especially 2D NMR, and chemical derivatization. The absolute configuration of 1 was determined by NOESY, CD, and Mosher's methods. Florxenilides A (1) and B (2) exhibited cytotoxicity against human colon cancer (WiDr) cells at 4.5 and 3.7 muM, respectively.