Tumor necrosis factor is multifunctional cytokine involved in various cell functions, such as differentiation, mitosis, angiogenesis, inflammation and immune controls. TNF-alpha plays also an important role in the control of metabolism. Its action on adipocytes includes increasing secretion of triglicerydes and inhibiting insulin action, controlling expression of some genes and modulating free fatty acid and leptin secretion. The review of the current literature on the TNF-alpha role in metabolism is presented in this paper.