Background & Objectives: Hypertension is one of the most important causes of premature preventable deaths in the world.The aim of the study was to evaluate the effect of family counseling on blood pressure on patients with hypertension. Methods: This is an experimental study. The sampling method was multi-stage Sampling. In the first stage 24 primary health centers was randomly selected and then randomly divided in two control and interventional groups. Then in each group based on age and sex 96 patients (n=96) were randomly selected. Inclusion criteria included having care records, the primary blood pressure and age over 30 years were. Data collection tool was a questionnaire that its validity and reliability confirmed by experts and Cornbrash’s alpha coefficient (79%). Counseling session was held for family member of patients in the intervention group for a month blood pressures before and 2 months after the intervention of measurement were recorded. Independent T test, paired and chi-square analysis were used to analyze data. Results: Unlike the control group, mean score of systolic pressure decreased significantly from 138.9 to 125.4 and diastolic pressure from 85.15 to 80.57 in interventional group (p<0.001). Conclusion: Counseling with the family has an effective role on blood pressure control and it is recommended to have an effective method to controlling blood pressure in health care.