Aldosterone production and zona glomerulosa size were studied in relation to salt intake in rats which were selectively bred for susceptibility (S) or resistance (R) to the hypertensive effect of high salt diet. With both in vitro or in vivo systems S rats suppressed aldosterone production In response to salt as much or more than Z animals. Zona glomerulosa mass was not different between S and R rats on various salt intakes. It is concluded that S rats are able to normally suppress aldosterone in response to salt in spite of their genetically controlled increment in adrenal 18–hydroxylase activity reported previously. (Endocrinology92: 1286, 1973)