DNA was extracted from the fossil termite Mastotermes electrodominicus preserved in Oligo-Miocene amber (25 million to 30 million years old). Fragments of mitochondrial [16S ribosomal DNA (rDNA)] and nuclear (18S rDNA) genes were amplified by polymerase chain reaction. Phylogenetic analysis of fossil and extant 18S rDNA confirmed morphological cladistic analyses of living dictyopterans (termites, cockroaches, and mantids). The fossil termite shares several sequence attributes with Mastotermes darwiniensis. Addition of this fossil to living-species phylogeny is required to substantiate Mastotermes monophyly and affects molecular phylogenetic hypotheses of termites in this, the oldest DNA yet characterized.