Bladder dysfunctions, particularly voiding disorders, are commonly seen in multiple sclerosis. 96% of those suffering from multiple sclerosis for more than ten years show urological findings. The impact on quality of life is high. Complications like hydronephrosis, stone formation, vesicourethral reflux, infections and renal failure can affect the upper urinary tract. Symptoms such as urgency, frequency, urinary incontinence and signs of obstruction, e.g. urinary retention, can, but need not be secondary to multiple sclerosis and may even present as primary clinical manifestation of the ailment. As multiple sclerosis is a dynamic disease with exacerbations and remissions, lower urinary tract symptoms and urodynamic findings change. Due to the poor correlation between symptoms, origin and bladder function, an initial urodynamic evaluation is advised. Therapy should be individualised, adapted to the stages of multiple sclerosis and planned in an interdisciplinary setting. Oral anticholinergics and intermittent self-catheterisation are important and effective treatments. Measurement of post-void residual bladder volume by ultrasound or catheterisation helps control therapy and bladder function. Cystoscopic botulinum-A toxin injection may be a promising new treatment option for many different urological dysfunctions. 10% of patients with bladder dysfunction, however, will still require surgery such as suprapubic cystostomy, augmentation cystoplasty, incontinent ileovesicostomy and sphincterotomy when conservative treatment fails.