A study of 35 patients with uncomplicated essential hypertension (EH) (labile hypertension, stages IB-IIA or stable hypertension, stage IIB) demonstrated a higher rate of Na+-Li+ countertransport in patients with hypertensive hereditary predisposition to EH (group 1), as compared to those with unaggravated heredity (group 2). A suppression of plasma renin activity (53%), and a higher rate of hyperlipoproteinemia (55%) were observed in group 1, as opposed to group 2 where Na+-Li+ countertransport was lower, plasma renin activity was normal, and hyperlipoproteinemia occurred in 33%. There was a direct correlation between Na+-Li+ countertransport and renin-angiotensin-aldosterone components in group 2. A conclusion is made that aggravated heredity, RAAS components and hyperlipoproteinemia should be taken into account in the assessment of Na+-Li+ countertransport in hypertensive patients.