Dietary intakes of tomatoes and tomato products containing lycopene have been shown to be associated with decreased risk of chronic diseases, such as cancer. Although several mechanisms, including modulation of gap junction communication and enhancement of immune system, are thought to be implicated in its beneficial activities, evidence is accumulating to suggest that lycopene may act as a modulator of intracellular reactive oxygen species (ROS) and, therefore, control ROS-mediated cell growth. According with this, at high concentration, ROS have been reported to be hazardous for living organisms, whereas at moderate concentrations, they play an important role as regulatory mediators in signaling processes regulating cell growth. In this review, we report the available evidence on a role of lycopene as a redox agent in cell proliferation, differentiation and apoptosis. In particular, we focused our attention on lycopene prevention of cell oxidative damage and its influence in cell growth as well as on lycopene modulation of redox-sensitive molecular targets in cell signalling: growth factors and growth factor receptors, antioxidant response elements, MAPKs, transcription factors, such as NF-κB and AP-1, and cytokine expression. Moreover, we speculate on the possible influence that lycopene may have as a redox agent in cancer.