A self-reported first-degree family history of hypertension was obtained by questionnaire in two consecutive subsamples of middle-aged male attenders to a multi-phased health screening program in Malmö. This corresponded to 2739 men in lower (36-39 years) and 6597 in upper (46-48 years) middle age. Reported first-degree family history of hypertension was very frequent, about 26-27% in both groups. It was predominantly confined to the parental generation and was twice as common in mother as in father. Furthermore, the reported family histories showed marked interrelations. Thus, hypertension was much more frequently reported when both parents had the condition than if it only concerned one of them. It is proposed that these findings may reflect an increased awareness, investigation, diagnosis and treatment of hypertension rather than the genetic occurrence of the disease per se in modern society.