This test is based on the physiologic character of mycobacterium, which produces carbon dioxide (CO2) during its growth, Löwenstein-Jensen media CO2 contents-were measured by gas chromatography for determining drug-resistance of mycobacteria. This was compared with the routine method. Seventy-eight mycobacteria were isolated from suspected tuberculosis patients for the experiment. Our data suggested that the accordance rates of both methods were 83.3%. Gas chromatography is a simple, rapid and accurate method for detecting drug-resistance. The results can be obtained twenty days earlier than by the routine method.