A high-pressure liquid chromatographic analysis for acebutolol and its major metabolite in blood, plasma and urine is reported. The analysis, in which the above mentioned compounds are chromatographed as ion pairs with dodecyl sulfonic acid, uses a simple and rapid method of sample preparation. The technique is more sensitive and rapid than those previously reported and it has equivalent or better reproducibility. The method is applied to the measurement in blood of acebutolol and its acetyl metabolite after a single oral dose.