Overactive bladder (OAB) characterized by symptoms of urinary incontinence, frequency, or urgency is a highly prevalent disorder that impacts the lives of millions of people in the US. OBJECTIVES: This study examines healthcare cost consequences of OAB among non-elderly adults, and factors that give rise to higher costs among patients with OAB. METHODS: Data were analyzed from patients 18 to 64 years of age who filed > one insurance claim between January 1994 and December 1995. Two patient cohorts were identified: 146,312 who received no OAB services and 2,385 who received OAB services. Multiple regression was used to breakdown cost differences between cohorts into 3 components: costs for OAB services, costs imposed by OAB on treating other conditions, and cost of treating additional medical problems in OAB patients. Pearson chi-square tests were used to assess differences between cohorts. RESULTS: OAB patients were primarily women over 40 with significantly higher relative risk of urogenital problems and depression than non-OAB patients (P =0 .001). OAB patients were also significantly more likely to be hospitalized and to stay longer (P =0.001). Average annual claims for OAB patients were $5,018 vs $1,767 for non-OAB patients. This difference was due to a greater prevalence of problems in OAB patients ($2456), receipt of OAB services ($161), and additional costs of non-OAB care ($634). CONCLUSIONS: Insurance claims for adult patients with OAB are higher than for non-OAB patients. The impact of OAB on non-OAB diseases may be a substantial cost driver. The use of effective and safe agents to treat OAB should have a significant impact on reducing the total costs of treating these patients.