OBJECTIVES: The National Institute for Clinical Excellence in the UK encourage provision of health-related quality of life (QoL) evidence for their assessments and recently their guidance has flagged the importance of patient preference in therapy selection. Gemcitabine plus cisplatin (GC) displays comparable efficacy to the methotrexate, vinblastine, doxorubicin plus cisplatin (MVAC) regimen in treating advanced bladder cancer but shows significant advantage in terms of tolerability and serious adverse events. Therefore a UK study was conducted to examine patient value associated with the toxicity profile of GC, compared with MVAC. METHODS: A novel application of discrete choice conjoint analysis was employed to quantify preference and time-trade-off utility differences providing sensitive strength of preference measures and utility values for individual treatment attributes. Differential toxicity attributes, that were patient relevant and clinically significant, were identified from head-to-head trial data. Attributes identified were: alopecia, weight loss, mucositis, diarrhoea, and febrile neutropenia/neutropenic sepsis. Fourteen oncologists and 16 oncology nurses served as patient proxies given the sensitive nature and ethical difficulties associated with the patient population. Respondents considered an orthogonally designed series of pair-wise choice scenarios representing incidence levels for individual toxicity attributes (treatment features) with trade-offs in life-expectancy. A logistic regression was utilised to analyse the stated scenario pair preferences against the individual attribute levels. Potential confounders were analysed. RESULTS: Survey results indicate a strong preference for GC treatment and a clear willingness-to-trade-time for tolerability benefits. Analysis of strength of preference for individual attributes shows strong support for treatment features that impact directly on QoL. CONCLUSIONS: UK respondents displayed a clear preference for GC treatment with superior toxicity offering a highly valued health related QoL gain. These results provide encouragement for further exploration, possibly by extension to the European setting. Discrete choice conjoint analysis is a promising instrument in the outcomes assessment of cancer therapies.