Although the inheritance of cpDNA and mtDNA has been well investigated in Pinaceae, there have been a limited number of reports in other families of coniferous plants. To clarify the inheritance of cpDNA and mtDNA in Chamaecyparis, one of the most important tree genus in Japan, interspecific hybrids of Chamaecyparis spp were investigated. The DNA of four hybrids from C. obtusa and C. pislfera crosses was digested with HindIII and hybridized with the tobacco cpDNA clone, pTB 8. All the hybrids showed the same pattern as the male parent, C. pislfera. The DNA of the hybrids was also digested with BgIIIand hybridized with the PCR-amplified mtDNA gene, cox I. All the hybrids showed the same Southern bybridization pattern as the male parent, C. pislfera. We conclude, therefore, that cpDNA and mtDNA are mainly inherited paternally in Chamaecyparis. We also observed a higher degree of interspecific polymorphism in the mtDNA than in the cpDNA.