THE possible presence of N-nitrosamines in cigarette smoke and/or condensate has been of interest for some years. Druckrey and Preussmann1 postulated that N-nitrosamines could be produced in burning tobacco, but the difficulty of measuring these compounds prevented the testing of this postulate. We have developed2 a gas chromatographic method for the selective detection of N-nitrosamines, and now report its application to the analysis of cigarette smoke condensate. We have identified N-dimethylnitrosamine (DMN) in cigarette smoke condensate, and shown that certain tobaccos grown in different conditions vary widely in their content of DMN.