Tomatoes are the richest source of lycopene, a potent antioxidant. Tomato products improve antioxidant defences and reduce the risk of inflammatory diseases, at least partly, due to the presence of lycopene. Lycopene, as an anti-inflammatory agent, prevents the production of inflammatory cytokines. Obesity is a chronic inflammatory condition in which the increased level of body fat leads to an increase in circulating inflammatory mediators. We hypothesised that the consumption of a lycopene-rich food would reduce inflammation in people who are overweight or obese. A total of 106 overweight or obese female students of the Tehran University of Medical Sciences were enrolled and randomly allocated to an intervention group (n 53) or a control group (n 53) consuming 330 ml/d of tomato juice or water, respectively, for 20 d. At baseline and day 20, serum concentrations of IL-6, IL-8, high-sensitivity C-reactive protein and TNF-α were analysed by ELISA and compared between the groups. Serum concentrations of IL-8 and TNF-α decreased significantly in the intervention group compared with the control group and with baseline. Subgroup analysis indicated that this effect was confined to subjects who were overweight. Among obese subjects, serum IL-6 concentration was decreased in the intervention group compared with the control group, with no differences in IL-8 and TNF-α observed. Tomato juice reduces inflammation in overweight and obese females. Thus, increasing tomato intake may provide a useful approach for reducing the risk of inflammatory diseases such as CVD and diabetes, which are associated with obesity.