Lonidamine, a derivate of indazole-3-carboxylic acid, is an antineoplastic drug with a typical mechanism of action. Lonidamine has no function on cellular nucleic acids or protein synthesis, whereas it exerts a powerful inhibitory effect on oxygen consumption, aerobic glycolysis and lactate transport and accumulation of neoplastic cells. Nevertheless, its proven ability to modify the permeability of membranes is consistent with the possible increase of drug uptake, reverse of drug resistance and triggering of apoptotic pathway. Lonidamine has been experimentally shown to potentiate the cytotoxic effects of anthracyclines in human breast cancer cell lines and cisplatin activity in both platinum-sensitive and platinum-resistant human ovarian carcinoma cell lines. Since the specific mechanism of action and side effects are not overlapping with those of standard antineoplastic agents, combination of lonidamine with standard chemotherapy has been widely investigated for the treatment of solid tumors. Additionally, the enhancement of radiotherapy activity by lonidamine has been considered for palliative therapy of lesions from metastatic cancers. The encouraging results of phase II-III trials for the treatment of advanced breast, ovarian and lung cancer must be confirmed by larger studies. Specifically designed studies to address the role of lonidamine in the adjuvant setting are warranted. Lonidamine, a dechlorinate derivative of indazole-3-carboxylic acid, has proved to exert a powerful antiproliferative effect and to impair the energy metabolism of neoplastic cells. Herein we review the current experience on combining lonidamine and chemotherapy and/or radiation therapy in the treatment of solid tumors. Several studies have been published on this topic. The total number of trials reported in literature and length of follow-up are still insufficient to draw a firm conclusion. However, the available data demonstrate a significant role of lonidamine in modulating anthracycline and platinum compound activity.