Fifteen members of a family had congenital colobomas of the optic nerves, all of which were bilateral. The bolobomas appeared as enlargement of the physiologic cup with severely affected eyes having huge cavities in the site of the disc. A variable amount of glial tissue was present within the colobomas. Either macular or extramacular serous detachment or sequelae were present in 21 of the 30 affected eyes, and often led to total blindness. Radioisotope cisternography in one patient failed to implicate cerebrospinal fluid as the source of the subretinal fluid. The disorder is apparently inherited as an autosomal dominant.