The article is devoted to one of the most complicated and least studied problems of modern surgery, traumatology and urology – the combined post-traumatic injuries of the pelvis and lower urinary tract. Current medical problem is that there is no clearly developed scheme of cooperative examination and management of such patients by urologists and traumatologists. The article considers etiological factors and mechanism of injury of the lower urinary tract in fractures of the pelvis. Particularities of of the anatomical structure of the pelvic and urogenital diaphragm and urethra are the basis for understanding the pathogenesis of urethral injury. In various fractures of pelvis and especially the front half ring, the most frequently damaged part of urethra is membranous and / or bulbous. Degree and severity of urethral damage (from strain to rupture) depends on the strength and speed of reduction of the pelvic diaphragm and the extent of damage and displacement of pelvic bones. Complications after pelvic trauma can manifest clinically by different voiding disorders: from acute urinary retention up to a total urinary incontinence. In males damage of the front half-ring of the pelvis and ischial bones often results erectile dysfunction. The successful solution of urological problems in these patients is possible only in case of cooperative actions of urologists and traumatologists. It is necessary to develop a diagnostic algorithm for patients with combined injuries of pelvis and urethra, to introduce modern methods of diagnostics and to develop an adequate phased treatment strategy.