To provide the first update of the EAU guidelines on assessment, therapy and follow-up of men with lower urinary tract symptoms (LUTS) suggestive of benign prostatic obstruction (BPO). A systematic literature review was conducted based on the results of a MEDLINE search concentrating on the years 1999-2003. In combination with expert opinions recommendations were made on the usefulness of diagnostic tests, therapeutic options and follow-up. During initial assessment the following tests are recommended: medical history, physical examination including digital-rectal examination, International Prostate Symptom Score, urinalysis, serum creatinine and prostate specific antigen measurement, uroflowmetry and post-void residual volume. All other tests are optional or not recommended. Aim of treatment is to improve LUTS and quality of life and to prevent severe BPE-related complications. Development of a 5alpha-reductase type I and II inhibitor and the data of the MTOPS trial providing scientific evidence for a combination therapy were the most significant innovations since the first version. Finally a more detailed knowledge on the natural history with identification of several risk factors for progression is the basis for a risk-profile orientated (preventive) therapy. Updated recommendations for assessment, treatment, and follow-up of patients with LUTS due to BPO are presented.