Intravesical botulinum toxin (BoNT-A) is a safe and effective treatment for overactive bladder syndrome. There are many reports on the clinical experience with BoNT-A, especially in patients with neurogenic detrusor overactivity. The US Food and Drug Administration has recently approved its use for idiopathic overactive bladder (iOAB). Various studies have reported positive results for iOAB in the short-term. Yet little is known about the results after repeated BoNT-A injections. In this study, we evaluated the long-term results of botulinum toxin (BoNT-A) in women with iOAB. Patients treated with BoNT-A from 2004 until 2009 were evaluated in a non-academic teaching hospital (Zuyderland MC, Heerlen, the Netherlands). All female patients with a follow-up of >5 years with idiopathic bladder dysfunction were included. All patients received 200 U of onabotulinum toxin-A in 20 intradetrusor injections. In some patients, we applied a dose adjustment for repeated injections. Patients were instructed how to use clean intermittent self-catheterization (CISC) before the treatment. We advised patients to commence CISC if post-void residual exceeded 150 ml. A total of 128 women were included. All patients had at least 5-year follow-up after their first injection. The mean follow-up was 97 (60-125) months. The mean age was 67 (46-88) years. Of all patients, 30 % were still on BoNT-A treatment at the last follow-up visit. Of the 70 % that discontinued treatment, 27 % had insufficient effect and 43 % had tolerability issues. Most patients discontinued treatment after the first (79 %) and second (19 %) injections. Only 2 % of patients discontinued treatment after more than two injections during follow-up. Intravesical BoNT-A is an effective treatment for women with idiopathic OAB. However, in time, almost two-thirds of patients in our study discontinued therapy. Most patients discontinue treatment after one or two injections and mainly due to tolerability issues.