OBJECTIVES: Acute otitis media (AOM) is a common pathology in children usually treated with an antibiotic given 2 or 3 times per day for 10 days. Non-compliance is often an issue and may explain in part the development of antimicrobial resistance. We conducted a Willingness to Pay study (WTP) to identify parents' preferences and assess the value given to a unique dose treatment in comparison with classical treatments. METHODS: Patients were accrued between February and November 2002. The study population was composed of parents of children with AOM who were interviewed by phone at the end of the AOM treatment. The questionnaire included three main topics: demographic characteristics, past medical history and history of present illness, quality of life assessment and treatment compliance. A multivariate analysis will be performed to estimate the various predictors of WTP. RESULTS: An analysis was performed on 595 respondents. Forty-six percent of the children were < 2 years and 33% were between 2 and 5 years of age. The majority (72%) attended day care center or school and most had received an antibiotic for AOM in the previous 6 months (45%). Parents were willing to pay an average (CAD mean, 95% CI) $31.54 ($29.42-33.65) for a unique dose treatment (n=562). The AOM treatment which had been received modified the parents's WTP (Anova, p=0.016) with azithromycin x 5 days (n=102) producing the smallest value $24.05 (19.75-28.34). Other treatments produced higher values: $32.31 (29.42-35.20) for amoxicillin (n=249); $32.83 (22.67-43.00) for amoxicillin-clavulanic acid (n=60) and $35.42 (31.47-39.37) for cefprozil (n=119). CONCLUSIONS: Parents of children who received azithromycin gave the smallest value while those whose children had received amoxicillin, amoxicillin-clavulanic acid or cefprozil gave the highest values Therefore, previously received antibiotic affects the magnitude of the WTP which is smaller for parents whose children had received shorter duration treatment.