Endoscopy is a minimally invasive diagnostic medical procedure used to evaluate the interior surfaces of an organ by inserting a small tube into the body, often, but not necessarily, through a natural body opening. Through the scope one is able to see lesions and other surface conditions.

The instrument may have a rigid or a flexible tube and not only provide an image, for visual inspection and photography, but also enable taking biopsies and retrieval of foreign objects. Endoscopy is the vehicle for minimally invasive surgery.

Many endoscopic procedures are relatively painless and, at worst, associated with mild discomfort although patients are sedated for most procedures. Complications are rare (only 5% of all operations).