The new version of the German guidelines for assessing benign prostatic hyperplasia (BPH) was written in 2006 and 2007 by experts of the BPH working group on behalf of the German Association of Urology and Federation of German Urologists. The full version is expected to be published in 2008. Recommendations for assessing BPH were modified and updated and include patient history, symptom questionnaires, physical examination, urine analysis, prostate-specific antigen, uroflowmetry, ultrasound examination of the urinary bladder (including postvoid residual urine), and ultrasound examination of the upper urinary tract or creatinine measurement. Optional tests are voiding diary, pressure-flow studies, ultrasound measurement of detrusor wall thickness, urethrocystography, and urethrocystoscopy. For the first time, tests for the differential diagnosis of bladder symptoms and BPH are described. Furthermore, the latest knowledge was added on disease progression, indications for urodynamic assessment, and ultrasound measurement of detrusor wall thickness for evaluating bladder outlet obstruction. International quality standards were applied in order to increase the guidelines’ value; all tests were judged using the levels of evidence and grades of recommendation of the U.S. Department of Health and Human Services classification.