In the United States, the most common causes of lower-extremity amputation are:

• Disease (70%)
• Trauma (22%)
• Congenital or Birth Defects (4%)
• Tumors (4%)

• Diseases that can cause amputation are varied, but the most common ones are vascular disease and diabetes. Vascular disease limits the circulation to the extremities. Diabetes, which affects blood sugar, can decrease the body's ability to heal itself.
• Trauma resulting in amputation is most frequently related to motor vehicle accidents and industrial accidents.
• Congenital malformation or birth defects can result in either the person having no limb or a very short limb that is treated as an amputation, for which a prosthetic device is made.
• Tumors of the bone, called osteosarcoma, can sometimes be treated by amputation of the limb.

Upper-extremity amputations, which are less common, are usually caused by trauma or birth defect; disease is not as great of a contributing factor. Common traumas that lead to amputation of the limbs include industrial accidents and burns.

The causes of amputation vary greatly from country to country. In countries with recent history of warfare and civil unrest, the amputation due to trauma and land-mine accidents is much greater.