The relative risks and complications increase proportionately according to the site, size, and type and complexity of the problem being addressed within the chest and in relation to the age of the patient and other comorbidities. This is principally related to the surgical accessibility, ability to correct the problem, functional reserve, technical ease, and the ability to achieve correction of the problem.The main serious complications are bleeding and infection, which can be minimized by the adequate exposure, mobilization, technical care, and avoiding injury and hematoma formation. Infection is the main sequel of tissue injury and hematoma formation and may arise from preexisting infection or be newly acquired. This can lead to urinary infection and systemic sepsis . Although very rare in children, multisystem failure and death remain serious potential complications from urologic surgery and systemic infection.This chapter therefore attempts to draw together in one place the estimated overall frequencies of the complications associated with urological procedures, based on information obtained from the literature and experience. Not all patients are at risk of the full range of listed complications. It must be individualized for each patient and their disease process but represents a guide and summary of the attendant risks, complications, and consequences.With these factors and facts in mind, the information given in this chapter must be appropriately and discernibly interpreted and used.