AN-Ident (Analytab Products, Inc., Plainview, N.Y.) is a ready-to-use system for anaerobe identification. It is based on the detection of constitutive preformed enzymes, is growth independent, and requires only 4 h of aerobic incubation. This micromethod was evaluated for its ability to identify anaerobic bacteria by using a conventional methodology as a reference. Of 265 clinical isolates, AN-Ident accurately identified 241 (91%) of the isolates to the species level and 259 (98%) of the isolates to the genus level, with limited supplemental testing needed (5%). The AN-Ident system performed well for the most common pathogens but less satisfactorily for infrequently isolated and/or asaccharolytic species; expansion and updating of the data base would be helpful. Although some color reactions were difficult to interpret, the commercial kit was easy to use.