SUMMARY Understanding the connection between sympathetic activity and essential hypertension is still rudimentary. We studied interrelationships of plasma catecholamines, plasma renin activity (PRA), aldosterone, sodium intake, and therapeutic response of 20 normal renin hypertensives. Based on plasma norepinephrine (NE), this population fell into two distinct subsets. The 11 patients in the "normal" NE subset had a basal NE of 257 ± 49 pg/ml (vs 250 ± 62 pg/ml in normotensives), while nine patients in the "high" range NE group averaged 522 ± 125 pg/ml. Both NE subsets showed significant correlation between mean arterial pressure (MAP) and NE. Only the "normal" NE subset showed significant correlation between MAP and PRA, and MAP and aldosterone. Correlations between changes in Na+excretion and NE, PRA, and aldosterone were all negative and statistically significant. Blood pressure was controlled in eight of 11 "normal" NE patients but only in one of nine "high" NE patients by restriction of Na+intake and/or use of a diuretic.