Zoledronic acid (ZOL) (Novartis Pharma, Basel, Switzerland) is a N-containing bisphosphonate currently used in the treatment of osteoporosis and tumour-induced bone disease in a wide range of solid and haematologic malignancies. Previous studies have shown that ZOL interferes with endothelial cell (EC) function; however, little is known about the effect of ZOL on ECs of the microvascular network that resemble the tumour vasculature. Taxol (Bristol-Myers Squibb Company, New York, USA), also known as paclitaxel (PAC) (Sigma, UK), is a chemotherapeutic agent currently used in anticancer therapy. Previous studies on tumour cells have shown that it specifically interferes with microtubule assembly. Its antiangiogenic properties in vitro or in vivo remain unestablished. Combination treatments with ZOL and PAC have also been shown to have a synergistic effect on apoptosis in tumour cell lines.