The genetics of primary angle-closure glaucome (a.c.g.) was studied: a) through the prevalence in sibs and children of a.c.g. probands, and b) through the family distribution of the closely correlated axial anterior chamber depth (ACD). The material emerged from an epidemiologic study in Greeland Eskimos. a) Compared with the general population, the observed prevalence of a.c.g. was increased in sibs of a.c.g. probands and the estimated, future prevalence was found to be the same in sibs and children. Age influence prevented a proper Mendelian analysis, but no simple monogenic inheritance seems probable. b) The biometric study showed a relatively shallow chamber in sibs, children, nephews, nieces and grandchildren of a.c.g. probands. Regression analyses revealed a corresponding pattern, also in control families of probands with shallow chambers and in general population families. A heritability of 70% was found, indicating that about two thirds of the age and sex independent variation in ACD seems to be genetic.