Abstract. Serum parathyroid hormone (PTH), phosphate, ionized calcium, magnesium, alkaline phosphatase and creatinine and the urinary excretion of phosphate and creatinine were studied after 1 and 3 weeks β‐blockade in 32 young healthy men given either atenolol at 50 mg. metoprolol at 100 mg, propranolol at 80 mg or placebo twice a day. After 1 week treatment serum phosphate (mean (range)) increased in the propranolol‐treated subjects (1.17 (0.99–1.30) to 1.32 (1.08–1.71) mmol l⁻¹ (P = 0.03), minor changes were found in the atenolol and the metoprolol‐treated subjects but not in the placebo group. Serum phosphate was unchanged compared to pretreatment values after 3 weeks. Renal clearance and urinary excretion of phosphate and creatinine was unchanged after both 1 and 3‐weeks treatment. Serum PTH, ionized calcium, magnesium and alkaline phosphatase were unchanged in all groups, whereas serum urate and creatinine increased in the metoprolol‐treated subjects after both 1 and 3 weeks. 1989 Blackwell Publishing Ltd