Tes-Tape is an indicator paper used in the form of small strips to test urine for the presence of glucose. The enzyme on the paper, glucose oxidase, acts on the beta-form of D-glucose in the presence of oxygen to liberate hydrogen peroxide, which in turn oxidizes the ortho-tolidine on the paper to a blue pigment. Improved methods of manufacture have helped to prevent deterioration of the enzyme and to increase the accuracy of the color readings. In performing the test it is necessary to make sure that glucose is present in the beta-form and that oxygen is available. Additional precautions are essential, especially in testing urine heavily loaded with glucose. It is recommended that the user lay the strip flat against a white background for reading and that, if the one-minute reading indicates 0.5 % (3+) glucose, a final reading be made at two minutes. The data here presented were obtained on both artificially made standard glucose solutions and naturally obtained specimens of diabetic urine. When used with due care, the Tes-Tape was both convenient and reliable for the semiquantitative estimation of urinary glucose.