This study investigated the chemical composition, anticancer, and antimicrobial activities in vitro of the essential oil isolated from the heartwood of Cunninghamia lanceolata var. konishii from Taiwan. The essential oil was isolated using hydrodistillation in a Clevenger-type apparatus, and characterized by GC-FID and GC-MS. Thirty-seven compounds were identified, representing 100% of the oil. The main components identified were cedrol (58.3%), alpha-cedrene (11.8%), alpha-terpineol (4.2%) and beta-cedrene (3.5%). The oil exhibited cytotoxic activity against human lung, liver and oral cancer cells. The active source compound was cedrol. The antimicrobial activity of the oil was tested by the disc diffusion and micro-broth dilution methods against ten microbial species. The oil exhibited strong growth suppression against Gram-positive bacteria and yeast with inhibition zones of 42-50 mm to MIC values of 31.25-62.5 microg/mL, respectively. For the antimicrobial activities of the oil, the active compound was determined to be cedrol.