Abstract: A new method for the determination of dipyrone (analgin) using a piezoelectric quartz crystal as detector has been proposed. An iodine-potassium iodide solution is added to the sample and the frequency shift of the crystal immersed in the sample solution with respect to the blank is directly proportional to the concentration of dipyrone over a range from 2×10^-7 to 3×10^-6 mol/L at pH 3.5～6.5 according to the equation C (mol/L)=6.85×10^-9 △F (Hz). No significant interterences were caused by commonly met inorganic substances, aminoaeids and a number of other organic substances. The method has been suggested for determining dipyrone at ppm level and in micro-samples of mg or μl level.