A report is given from an on-going multicenter trial in Sweden, in which 117 hypertensive patients have been treated with a new cardioselective beta-adrenergic blocking agent, atenolol (ICI 66.082, Tenormin) for an average of six months (range 2-21). Statistically significant reductions of BP were observed, recumbent by 29/19 mmHg (p less than 0.0001) and standing by 28/18 mmHg (p less than 0.0001). Few and comparatively mild side-effects were seen.