Molecular taxonomic relationships of the genus Auricularia, together with outgroup of Tremella, were studied using random amplified polymorphic DNA. Eight species of Auricularia and two species of Tremella were examined. The dendrogram derived from RAPD data by UPGMA suggested that the genera Auricularia and Tremella would be monophyletic. For Auricularia, three distinct genetic groups were recognized: the first included A. peltata and A. cornea; the second included all strains of A.auricula; the third included five morphological species of A. delicata, A. fuscosuccinea, A. polytricha, A. maxima and A. reticulata. This molecular taxonomy suggests that A.cornea and A. polytricha would be two different species and not synonymous, and the presence or absence of a medulla in cross-section of the basidiocarps would not indicate whether or not taxa are closely related.