OBJECTIVE: To estimate prevalence of Urinary Incontinence (UI) in the Portuguese population. To determine the costs of treatment (including incontinent pad usage) with Tolterodine for patients suffering from chronic UI. METHODS: Data from the National Health Survey performed in 1995-96, involving a representative sample of 49718 people across mainland Portugal, was analyzed to determine age, sex-specific and age-standardized prevalence rates of UI. The average consumption of pads by incontinent patients was estimated from the information provided by the Centro Regional de Saúde from Madeira Island, a region where pads are reimbursed. RESULTS: The global prevalence of urinary incontinence in Portugal was of 4,3%, being 2,6% in males and 5,8% in females. Age and sex adjusted prevalence rates were of 1,9 % in males while 4,4 % in females. Age and sex specific prevalence rates increase with age from 15 years onwards in both sexes, being higher in females across all age groups. Above 65 years of age 10% of men and 12 % of women suffer from urinary incontinence. Of these, 68,8% are likely to suffer from chronic urinary incontinence. This is the estimated burden of the disease in the general Portuguese population. Urinary incontinent chronic patients use on average 4 pads per 24 hours, normally using 3 pads during the day and 1 pad at night. Comparing the average pad costs per day with using Tolterodine, the difference is remarkable (648$00 PTE versus 334$60 PTE). The economic impact of such use would reduce the health expenditure in UI patients significantly. CONCLUSION: The prevalence of UI in Portugal is within the limits of what is mentioned in other community-based studies. The average daily costs of treatment with Tolterodine are lower when compared with pad usage.