Renal transplant is the treatment of choice for end-stage renal disease. Perirenal fluid collections are a common surgical complication postrenal transplant that may lead to early graft loss, considerable morbidity, and excess financial loss, if not diagnosed and managed early. The causes of posttransplant fluid collections are urinary leak, lymphocele, hematoma, and seroma, which can be further complicated by abscess formation if becomes infected. Urine leak is considered the most common urological complication postrenal transplant. Diagnosis can be made by biochemical analysis of the fluid drainage with the simultaneous comparison to that of serum. Radiological imaging is also essential for confirming the diagnosis of urinary leak that may not necessarily identify the site of the leak. The management of urinary leak is usually surgical unless the leak is small. The choice of surgery depends on the location of the leak, the vascularization of the involved ureter, and the presence of any complications caused by the leak. This article reviews the differential diagnoses of perirenal fluid collections in postrenal transplant period and focuses on the clinical assessment of urinoma and management options according to the latest evidence-based medicine.