A procedure has been developed for the qualitative and quantitative determination of niacin and niacinamide by gas-liquid chromatography. Niacin was determined as its ethyl ester (ethyl nicotinate) or as N -ethylnicotinamide. Niacinamide was determined as niacinamide or converted to either ethyl nicotinate or N -ethylnicotinamide. An immobile biphase of 2.5 percent NPGS–10 percent SE-30 was the most satisfactory immobile phase evaluated. The results revealed that, in general, this sensitive gas-liquid chromatographic method could detect 5, 8, and 10 ng. of ethyl nicotinate, N -ethylnicotinamide, and niacinamide, respectively, using the hydrogen flame-ionization detector. The β -argon ionization detector (Ra 226 ) detected 15, 20, and 25 ng. of each compound, respectively. It was found that increasing quantities of ethyl nicotinate, N -ethylniacinamide, and niacinamide gave linear responses.