Port-Orford cedar ( Chamaecyparis lawsoniana ), Alaska yellow cedar ( Chamaecyparis nootkatensis ), and Eastern red cedar ( Juniperus virginiana ) were submitted to supercritical fluid extraction with CO 2 (SCC) and Soxhlet extracted (SE) with hexane. The components in the extracted oils were identified by GC-MS. The oils were evaluated against two common wood decay fungi, brown-rot fungus ( Gloeophyllum trabeum ) and white-rot fungus ( Trametes versicolor ). The SCC extraction yields of J. virginiana , C. nootkatensis , and C. lawsoniana were 3.27%, 3.22%, and 3.29%, respectively. The SE yields of J. virginiana , C. nootkatensis , and C. lawsoniana were 0.80%, 0.71%, and 1.52%, respectively. The statistical analysis showed that SCC extracted cedar oils had higher antifungal activities than SE cedar oils against both fungi. In vitro studies showed that C. nootkatensis oils have the strongest antifungal activity, followed by C. lawsoniana, and J. virginiana oil.