Goniotomy is an effective treatment for primary infantile glaucoma. Because a cloudy cornea may prevent a clear view of the anterior chamber angle through the operating microscope, we investigated whether an endoscope can be combined with a cutting laser to perform laser goniotomy in a surgical model of primary infantile glaucoma. The anterior chambers of cadaver procine eyes were deepened with a viscoelastic material. A 300-micron-diameter silica fiber coupled to an Olympus 0.8-mm-diameter flexible fiber optic endoscope entered the anterior chambers through 4-mm corneal incisions. The anterior chamber angles were clearly observed on a videoscreen as the endoscopic fiber optic laser scalpel approached the pectinate ligaments. With the guidance of a He-Ne aiming beam, the anterior chamber angle pectinate ligaments were cut over a 160 degree arc with a pulsed Ho:YAG laser (2.1 micrometers wavelength, 50 mJ, 5 Hz repetition). The specimens were fixed in glutaraldehyde and processed for scanning electron microscopy, or fixed in formalin and processed for light microscopy. The treated area demonstrated incision of the pectinate ligaments with opening of the underlying trabecular meshwork. The edoscopic fiber optic laser scalpel is capable of cutting the pectinate ligaments in a surgical model of primary infantile glaucoma. Therefore, it may be a useful instrument for performing goniotomy when a cloudy cornea in primary infantile glaucoma prevents visualization of the anterior chamber angle with a goniotomy lens.