A technically simple method of testing the sensitivity of tubercle bacilli to tuberculostatic agents is described which gives accurate results directly from positive sputum in one or two weeks. Parallel slide and tube sensitivity tests against streptomycin and isoniazid on 136 specimens show 49% and 68% agreement respectively. The number of cultures within the sensitive range of each drug was almost identical. The advantages of slide sensitivity testing over conventional methods are technical simplicity and rapid results.