Aim:
Background: Endocrine dysfunction is the source of both diabetes and thyroid disorders, and it has been shown that these conditions affect one another. Appropriate glycemic control can lower the occurrence of hypothyroidism, which is more common in T2DM patients. Neopterin is a sensitive indicator of infectious illnesses linked to heightened cellular immune system activity. Objectives: This study aim to investigate the variation in Neopterin serum levels between adult individuals (T2DM with hypothyroidism and without Hypothyroidism).

Material and methods:
Materials and methods: Ninety participants were divided into three group: (30) T2DM with Hypothyroidism patients, (30) T2DM without Hypothyroidism patients and (30) Control. They were obtained from national diabetes center, Mustansiriyah University.

Results:
Results: At P<0.001 a highly significant different increase of neopterin levels among three groups. The level of Neopterin in T2DM with Hypothyroidism patients, and T2DM without Hypothyroidism patients have a positive correlation coefficient with P<0.05 of the BMI, HbA1c, TC, TG, AIP and TSH. Furthermore, a positive correlation with P<0.01 to FBS, HOMA-IR and LDL-C.

Conclusions:
Conclusion: The elevated levels of neopterin in type 2 diabetic patients with hypothyroidism and without hypothyroidism play as a regulator of energy consumption, leading to the hypothesis that thyroid gland disease may influence its level. In addition, the potential for use as a diagnostic marker for diabetics with thyroid disease due to the occurrence of complications of diabetes, including cardiovascular diseases.