Relaxation is a basic nursing intervention of to decrease the blood glucose level of diabetes mellitus patients. The aim of this study was to compare blood glucose level before and after relaxation on the experiment and control group of type 2 diabetes mellitus patients at a hospital in Tasikmalaya, West Java. This quasi experiment study with control group involved 100 participants, divided equally into the experiment and control group. Fifty participants were trained the relaxation technique whilst the control group didn’t. The difference of blood glucose level before and after relaxation was examined by the pairedsample T test. The blood level serum were significantly decreased about 53,6 mg/dL after relaxation with p value 0,000. The decreasing rate reached its highest on seventh day after relaxation whereas the lowest was on the third day after relaxation. In conclusion, relaxation can decrease the blood glucose level of the diabetic mellitus type 2 patients.