A simple and improved stability-indicating gas liquid chromatographic procedure using flame ionization detection is described for the determination of lidocaine hydrochloride in solution in the presence of N, N'-diethyl-methyl-glycine xylidide as internal standard (IST). This method is capable of distinguishing the intact drug from its thermal degradation products. A linear relationship between peak height ratio (lidocaine-HC1/IST) and lidocaine-HCl concentrations is found in the range of 10-50 μg/ml. The least squares regression line is Y=55.0 x + .0121 with a correlation coefficient of 0.998. The percent coefficient of variation of the assay within days is estimated at 2.12%.