OBJECTIVE: To relate lipid levels in middle-aged men to that of their fathers at 50 years of age measured 30 years earlier. DESIGN AND SUBJECTS: In 1963, 855 men born in 1913 took part in a cardiovascular risk factor survey when they were at 50 years of age. In 1993, 475 sons to these men, aged 44-56, were invited to another examination; 263 of these men were examined (response rate: 56%) and compared with their 217 fathers when they were examined at 50 years of age in 1963. In the 1993 survey, 798 men aged 50, were also examined, from a general population sample of men born in 1943 (response rate: 55%). SETTING: City of G?teborg, Sweden. MAIN OUTCOME MEASURES: Serum lipids in sons as a function of lipids in their fathers. RESULTS: Compared with the men born in 1913, both sons and men born in 1943 had lower mean serum cholesterol, but higher body mass index (BMI) and serum triglycerides. There was a significant relation between serum cholesterol in sons and their fathers (r = 0.25; P 6.9 mmol x L(-1)), 37% had serum cholesterol above 6.5 mmol x L(-1), compared with 16% amongst sons to fathers in the lowest quartile (