A 74-year-old man suffering from hypertension had transient loss of strength in his left arm and leg. His severe hypertensive spells were caused by high-pressure chronic bladder retention. The patient had benign hyperplasia of the prostate for which transvesical enucleation was performed. The blood pressure then returned to normal. The transient neurological deficits had probably been caused by the abrupt blood pressure changes. In older male patients the possibility of this reversible cause of hypertension should be kept in mind.