A non-functioning kidney, also known as a non-viable or atrophic kidney, is a kidney that has lost its ability to perform its normal physiological functions effectively. This condition can result from various factors such as chronic kidney disease, severe kidney infection, urinary tract obstruction, or vascular disorders affecting blood flow to the kidney. Symptoms may be minimal or absent, but some individuals may experience flank pain, urinary tract infections, or high blood pressure. Diagnosis typically involves imaging studies such as ultrasound, CT scan, or MRI, which can reveal structural abnormalities and decreased kidney size and function. Treatment options depend on the underlying cause and severity of kidney dysfunction and may include conservative management with regular monitoring, medication to control symptoms, or surgical removal of the non-functioning kidney in cases of significant complications or risk of infection.