To evaluate the differential effects of beta-blockers on serum lipids and apolipoproteins in normolipidaemic and dyslipidaemic hypertensives, 330 patients with mild to moderate essential hypertension were studied 1 month after placebo therapy and 6 months after monotherapy with propranolol (n = 53), atenolol (n = 66), metoprolol (n = 58), pindolol (n = 53), or celiprolol (n = 100). Serum total cholesterol, triglycerides, high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), and apolipoproteins (Apo) A1 and B were measured at baseline and study end. A total of 136 (41.2%) patients were considered normolipidaemic (pretreatment LDL-C < 160 mg.dl-1) and 194 (58.8%) were considered dyslipidaemic (LDL-C > 160 mg.dl-1). Changes in total cholesterol differed between normolipidaemics and dyslipidaemics with propranolol (+13% in normolipidaemics vs -0.5% in dyslipidaemics, P < 0.001), atenolol (+7% vs -2%, P = 0.01), metoprolol (+9% vs -4%, P0.0006), pindolol (+8% vs -9%, P < 0.001), and celiprolol (-1% vs -13%, P = 0.002). HDL-C differed less, with propranolol (-18% vs -13%), atenolol (-6% vs -2%), metoprolol (-2% vs -6%), pindolol (+4% vs +1%), and celiprolol (+9% vs +4%); none of these changes between normolipidaemic and dyslipidaemic patients were statistically significant. LDL-C changes differed the most, with propranolol (+35% vs -1%, P < 0.0001), atenolol (+15% vs -4%, P = 0.001), metoprolol (+12% vs -6%, P = 0.004), pindolol (+12% vs -13%, P < 0.0001), and celiprolol (+3% vs -16%, P = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)