Chronic lower urinary tract dysfunction can be treated by sacral neuro-stimulation. Clinical parameters for selection of patients for this expensive and invasive treatment modality are not well defined to date. Therefore, before implantation of a permanent stimulator, the effect is tested by temporary implantation of a wire electrode connected to an external stimulator. According to the literature, many patients do not respond during temporary implantation and a mean of 25% of the patients with a permanent stimulator implanted fail to respond as well. To improve patient selection, we attempted to define clinical parameters to predict the outcome of sacral neuro-stimulation in 100 consecutive patients who were tested with temporary sacral stimulation. A total of 34 patients achieved a complete cure on trial stimulation. It appeared that detrusor overactivity and urethral instability responded best but they were not predictors of success. We conclude that neither gender, patient age, history nor diagnosis are predictors of success in sacral neuro-stimulation of lower urinary tract dysfunction.