The morphological and physiological characteristics of 44 isolates of Exophiala werneckii recovered from human and environmental sources were indistinguishable from 2 isolates that caused tinea nigra. Casein hydrolysis and inability to decompose tyrosine differentiate E. werneckii from Exophiala jeanselmei, Exophiala spinifera, and Wangiella dermatitidis.