The identity of heath-leaved cypress is controversial. In this study nucleotide sequences of nuclear ribosomal DNA were used to identify heath-leaved cypress (Chamaecyparis `Ericoides') species. Sixteen individuals were sampled representing the five species of Chamaecyparis, `Ericoides', and four other genera of Cupressaceae (Cupressus, Fokienia, Juniperus, and Thuja). The results placed `Ericoides' unequivocally to Chamaecyparis thyoides, supporting a conclusion derived from wood anatomy. This study supports the usefulness and integrity of using molecular data to identify the genetic affinity of cultivars that are morphologically different from the parent species.