Vinflunine is a novel vinca alkaloid developed through the selective modification of vinorelbine using super-acidic chemistry. In preclinical testing, vinflunine demonstrated significantly enhanced anti-tumour activity in human tumour xenograft models when compared to its parent compound. A phase I study was conducted to evaluate the safety and toxicity of vinflunine administered as a 10 minute intravenous infusion on days 1 and 8 every three weeks. Sixteen patients with advanced solid tumours were treated. Two of four patients experienced dose limiting toxicities (DLT) at 190 mg/m2 and this was established as the maximum tolerated dose (MTD). At the MTD, the DLT of vinflunine consisted of constipation and neutropenia. Fatigue was notable but not dose limiting. No objective responses were observed. A dose of 170 mg/m2 given on a day 1 and 8 schedule every three weeks would be suitable for future studies.