This exploratory study examined the effect of structured teaching about essential hypertension on control of the diastolic blood pressure in individuals with a diagnosis of essential hypertension. Using the pre-test, post-test design, study participants were measured on knowledge about essential hypertension and diastolic blood pressure before and after intervention. Six hypotheses were tested, three related to control of blood pressure, and three related to knowledge about essential hypertension. There was no significant difference between the experimental and control groups on diastolic blood pressure readings at the conclusion of the study. There was a significant difference between the experimental and control groups on post-test scores on knowledge of essential hypertension. It was concluded that structured teaching had no significant effect upon control of the diastolic blood pressure. Instruction increased knowledge, but not blood pressure control.