The purpose of this study is to determine whether the Guardian Continuous Glucose Monitoring System in the home setting is more useful than frequent self blood glucose monitoring with a view to modifying patient's diet and exercise habits or improvement self disease control efforts and at last glycemic control in patients with type 2 diabetes

In diabetes management, compliance, disease awareness and empowerment of the patient play an important role and the immediate feedback on the effects of diet and exercise that the self monitoring blood glucose (SMBG) may provide, could enhance patient empowerment. Increased use of SMBG has been shown to be associated with improved medication compliance and better metabolic control by several studies. However, because of many factors, including pain and inconvenience, many diabetic patients do not accept frequent fingersticks for self blood glucose monitoring (SBGM) levels. In addition, the SBGM result gives the data for only a few seconds, without any information on glucose trends.

So we need new glucose monitoring method that could reflect glucose trends and glycemic excursion continuously because glucose monitoring still remains the cornerstone of evaluating the efficacy of therapy and motivating self disease control in subjects with diabetes.

Few studies have examined the effects of real time continuous glucose monitoring system targeting type 2 diabetes. So our goal is to determine whether the Guardian Continuous Glucose Monitoring System in the home setting is more useful than frequent self blood glucose monitoring with a view to modifying patient's diet and exercise habits or improvement self disease control efforts and at last glycemic control in patients with type 2 diabetes

Inclusion Criteria:

• Type 2 diabetes
• Group 1: HbA1c < 8% with a stable insulin or oral hypoglycemic agents (OHA) regimen for the prior 2 months with no plans to switch modality of insulin or OHA administration during the next 3months.
• Group 2: HbA1c >= 8% and the fasting blood glucose must be < 130 at the same time with a stable insulin or oral hypoglycemic agents (OHA) regimen for the prior 2 months with no plans to switch modality of insulin or OHA administration during the next 3months

Exclusion Criteria:

• Use of corticosteroids or hormone therapy within the last 6 months
• Presence of another chronic illness