The blood glucose of 271 diabetic subjects (140 boys and 131 girls), followed in a diabetes clinic, was determined by three methods: 1) Reflectance Meter (Ames), 2) Eyetone (Ames), and 3) AutoAnalyzer (Technicon). The results were statistically analyzed at four blood glucose concentration ranges (less than 100, 100 to 200, 201 to 300 and greater than 300 mg/dl). The Eyetone instrument and the Reflectance Meter were found to be simple and exact methods for instant glucose determination as compared with the standard AutoAnalyzer technique. The Reflectance Meter was inexact in the blood glucose range of 201 to 300 mg/dl. The Eyetone instrument was reliable within the range of 10 to 400 mg/dl and was found to be useful for quick glucose determination in the clinic or home.