The purpose of this study is to establish a new, non - invasive diagnostic technique for peripheral circulation in patients with diabetes mellitus in the early stage of arteriosclerosis obliterans (ASO) as one of the complications of diabetes mellitus. We observed peripheral circulation quantitatively by thermography and Laser- Doppler blood flowmetry. The body surface peripheral circulation in 27 patients with diabetes mellitus, including 14 males and 13 females with a mean age of 67.4 years (range from 51-82 years), and with a mean hemoglobin A1C (HbA1C) 019.5% (range from 6.8%-13.0%), and who were suffering coldness, numbness or pain in their feet, was examined using thermography and Laser- Doppler blood flowmetry. Thermographic results were analyzed quantitatively by calculating a recovery ratio as : Recovery ratio= [Total counts of thermography (Pixels) over temperature (T) after cold -loading] + [Initial counts over T after hot-loading] Xl00 (%). Results of recovery ratios for 27 cases were 0% - 93.5%, and the average was 34.0%. At the same time, the blood flow after cold -loading was 0.91 - 5. 36ml/min/lOOg tissue and the average was 2.04ml/min/l00g tissue. We found that the recovery ratio and the blood flow were correlated (r=O. 634, p