Background: Diabetes mellitus (DM), commonest metabolic illness, is one of the major public health concerns worldwide. Objectives: To inspect the clinical importance of serum copeptin in patients of type 2 diabetes with and without nephropathy and to assess the relation between microvascular complication of type 2 diabetic patients and copeptin plasma levels. Patients and Methods: The study was conducted between November 2021 till May 2022, included 90 participants; 30 healthy age and sex matched control participants, 20 cases of DN with normoalbuminuria, 20 cases of DN with microalbuminuria, and 20 cases of DN with macroalbuminuria. Serum copeptin levels were measured by ELISA, Blood Urea Nitrogen (BUN), creatinine, Glycosylated Hemoglobin (HbA1c), and spot urinary albumin creatinine ratio (UACR) were done using spectrophotometry. Results: it was shown that serum copeptin level in patients with diabetic nephropathy with macro albuminuria was significantly lower than in healthy control people. There was no significant difference in level of serum copeptin in normal or abnormal fundus examination, neurological examination. Conclusion: serum copeptin level in patients with diabetic nephropathy with macroalbuminuria is significantly lower than in normal healthy control. There was no significant association was found between serum copeptin level, diabetic retinopathy nor neuropathy.