Objectives: Intraperitoneal bladder rupture, a frequent surgical emergency, needs a early diagnosis and prompt treatment. The current measure in theory and practice to diagnose them is retrograde cystography with X ray or CT scan. This method practically have had many disadvantages so that the authors have carried out a study on another test with many advantages to diagnose the intraperitoneal bladder rupture. Materials and method: Cross sectional, descriptive and prospective study on patients present the clinical findings suspected intraperitoneal bladder ruptures such as abdominal contusion, gross hematuria, hypogastric tenderness, liquid in hypogastric region by sonography. For these patients, the authors made a bedside sonography with retrograde instillation of normal saline (300 - 500 ml) to monitor the bladder size (empty or full) and to know the amount of urine withdrawn afterward: empty bladder: test (+)
full bladder: test (-). The final diagnosis was confirmed by results of operation or clinical courses. Results: During 2 years (2010-2011) the authors have 18 patients in which 7 patients suffered from poly traumas with serious clinical presentations as traumatic shock (6 cases), coma due to associated cerebral injuries using respirators (3 cases). 14 patients with test (+) the authors performed operation immediately and found bladder rupture intraperitoneally. 4 patients with test (-) the authors used non surgical treatment and they all were normal afterward. Sensitivity was 100 percent and specificity was 100 percent. Conclusions: it is a simple, effective and safe test to confirm or to rule out the injuries of intraperitoneal bladder ruptures.