We presented a familial case of congenital microcoria associated with late onset congenital glaucoma. The proband, a 36-year-old man, had abnormally small pupils with diameters of 3.5 mm in the right eye and 1.5 mm in the left. Mydriatics, such as 1.25% epinephrine, 5% neosynephrine, 5% tyramine, and 1% atropine did not dilate the pupils fully. The iris showed poor development of collarettes and crypts, and lacked circular contraction folds bilaterally. Gonioscopic examination revealed developmental anomalies of the anterior chamber angles in both eyes. Abundant iris processes, which fused together partially in the right and circumferentially in the left, inserted from the iris root onto the scleral spur or further near to the Schwalbe's line. Applanation tonometry measured high intraocular pressure in both eyes. The anterior chamber angle tissues obtained by trabeculectomy were studied histopathologically. In the trabecular meshwork, a thick endothelial meshwork with many layers of cells embedded in prominent extracellular materials was observed on the canal side. On the anterior chamber side, there were several layers of trabecular sheet. These findings indicate underdevelopment of the trabecular meshwork. We examined three generations of his family and found that 5 members showed bilateral congenital microcoria, and another, deceased, was said also to have had congenital microcoria. All 5 surviving patients (3 males and 2 females) with microcoria were found to have bilateral goniodysgenesis also. Two of the 5 were affected with bilateral late onset congenital glaucoma. The congenital disorders in this family, congenital microcoria and goniodysgenesis, appeared in close relation, and were transmitted by autosomal dominant inheritance.