Rapid processing of specimens without sacrificing accuracy is of utmost importance in clinical laboratories. To effect this in the bacteriology laboratory, there should be cognizance of the frequency of occurrence of the species that will be subject to identification and the salient features of those frequently encountered species. Since Enterobacteriaceae comprise approximately 75% of all aerobic Gram-negative bacilli isolated in clinical laboratories, it is a common and pragmatic practice to process all enteric-like isolates as though they are, indeed, members of this group. An important source of difficulty in identification of nonfermenters arises from using inappropriate media. Often these media were developed for enteric bacteriology and may well yield misleading or erroneous results in nonfermenter bacteriology. The CDC method, though somewhat less sensitive and not applicable to organic salts and nitrogenous compounds, is preferable in respect to immediate availability and ease of inoculation.