Abstract: An endoscope of such small size and flexibility to allow safe diagnosis and treatment of lesions and disorders of the ureter and kidney. A 2mm outer diameter tube fabricated from a low friction material includes a bundle of fiber optics shaped to conform to an inner sector of the tube. This bundle provides illumination while a second fiber optic bundle, bonded alongside the first bundle, permits observation at a distal end. The remainder of the interior of the tube defines a longitudinal duct for the bidirectional exchange of fluids. The internal disposition of the fiber bundles and duct keeps the dimensions small enough to permit ureteral and renal applications as well as other heretofore inaccessible places.