Familial resemblance of blood pressure (BP) was studied in 545 families of which 370 included natural children, 24 adopted children and 151 both natural and adopted children. Mean values of four automatic BP measurements (Dinamap 845) were converted into age (adult) or height (children) and sex adjusted scores. BP was compared between parents and randomly chosen index children. A significant resemblance of BP was observed between natural children and their parents: r = 0.24 for systolic BP, r = 0.29 for diastolic BP, (n = 272 p greater than 0.05). BP of adopted children did not resemble that of their foster parents except for a significant correlation to BP of the adopting mothers (n = 46). Weight, heart rate, age and time of common life shared did not influence the results. The relative contribution of genetic and common environmental factors to BP correlation between family members could not be evaluated in this study. BP of children whose parents have high BP should be monitored regularly.