OBJECTIVES: The objective of this study was to use conjoint analysis (CA) to measure patients' valuations of the characteristics of drugs used to treat overactive bladder (OAB) in monetary terms. METHODS: A CA survey using a discrete choice method was administered in interviews with OAB patients in three clinics in the UK between July 1999 and April 2000. The survey consisted of a series of pairs of hypothetical OAB drug profiles described in terms of treatment attributes with varying levels. For each pair the patients were asked to select the drug profile they preferred. The drug profiles included efficacy attributes (e.g. reduction in urinary incontinence) and side-effect attributes (e.g. incidence of dry mouth). A cost attribute was included to allow the calculation of patients' valuations of the different attributes in monetary terms. RESULTS: One thousand five hundred and twenty discrete choice comparisons of hypothetical OAB drug treatments were obtained from 95 patients. Based on these responses, a logit model was estimated that attempted to explain the reasons why the respondents made the choices they did. From this model, it is possible to derive estimates of the implied willingness-to-pay (WTP) of patients for improvements in OAB drug efficacy rates and for the incidence of OAB drug-related side effects. Improvements in efficacy attributes have positive WTP estimates (from £2.20 to £11.22 per day) and the WTP estimates are negative for the incidence of side-effect attributes (from -£2.79 to -£9.83 per day). CONCLUSIONS: This study demonstrates the capability of the CA technique to measure valuations of varying drug profiles in monetary terms. The results of this study could be used to estimate the WTP of patients for different OAB drug treatments.