There has been a growing interest in the potential role of proinflammatory cytokines in the aetiology of insulin resistance. Tumour necrosis factor-a inhibits insulin signalling in adipocytes and skeletal muscle, actions that may be shared with interleukin-6. In a study of 107 healthy subjects, we have found close correlations of circulating levels these proinflammatory cytokines, and of C-reactive protein, with a number of components of the insulin resistance syndrome.