Calocedimers A, B, C, and D, together with four known compounds, platydiol, α-cadinol, ferrugiol, and 6,7-dehydroferrugiol, were isolated from the bark of Calocedrus macrolepis var. formosana. Calocedimers A, B, C, and D are the dimers of abietane-O-camphane, abietane-O-cadinane, abietane-O-abietane, and abietane-O-abietane, respectively. Their structures were elucidated from spectroscopic data.