[Purpose] The current study aimed to investigate the reliability of infrared thermography as a method of determining foot skin temperature, and to determine the relationship between foot skin temperature and blood flow in type 2 diabetes mellitus (DM) patients. [Participants and Methods] Eighty-five patients were recruited and their foot skin temperature and the ankle brachial index (ABI) were measured using infrared thermography and an automated oscillometry, respectively. A correlation between foot skin temperature and blood flow was performed. The patients were screened and classified according to two groups; diabetic peripheral neuropathy (DPN) and non-DPN. Discriminant validity was determined by comparing the foot skin temperature between the two groups. [Results] The test-retest reliability of foot skin temperature was high. A positive correlation was found between foot skin temperature and ABI in both feet. The foot skin temperatures in the DPN group were found to be significant lower when compared with those in the non-DPN group. [Conclusion] Foot skin temperature is an indirect method of evaluating blood flow in the feet of diabetic patients and can be used as a clinical outcome measurement of treatments used to improve blood flow in type 2 DM patients.