The aim of this double blind placebo controlled clinical trial is to investigate the effects of melatonin on glucose and lipids profile in type II diabetic patients. This study will be conducted as a before and after design and 76 patients who have inclusion criteria (diabetes mellitus type II, serum Cr<2mg/dl, HbA1c<8.5%) will receive placebo 2 tab/day for 12 weeks and then melatonin 6mg/day for another 12 weeks. Exclusion criteria will be melatonin consumption, pregnancy or breast feeding, current or history of epilepsy, smoking, drug addiction, alcohol or amphetamine abuse, warfarin or nifidipin medication, shifting job, history of coagulopathy or bleeding, change in diabetic or anti lipid treatment protocol, starting treatment by beta-blockers or diuretics. FBS and lipid profile will be measured in first evaluation and weeks 12 and 24.