Background: Inflammatory cytokines have potential to enhance insulin resistance, prediabetes and hence type 2 diabetes mellitus (T2DM). Tumor necrosis factor alpha (TNF-α) is a cytokine that is released by adipocytes and inflammatory cells in response to chronic inflammation. The current research was taken to study the role of TNF-α in pathogenesis of prediabetes and new onset T2DM in Egyptian subjects. Objective: Measurement of TNF-α level in prediabetics, treatment naive T2DM patients, and healthy persons to assess its possible role in management. Subjects and methods: This study included 30 patients with treatment naive T2DM, 30 prediabetics and 30 control subjects. We assessed serum TNF-α level in all groups by enzyme linked immunosorbent assay (ELISA). Results: Our study showed a significantly higher level of TNF-α in T2DM patients compared to prediabetics and control subjects. TNF-α showed positive correlation with HBA1c. Conclusion: TNF-α is associated with concurrent prediabetes and T2DM and correlates positively with HBA1c.