Determination of lipoprotein patterns and of major plasma lipids was carried out in 171 patients with strokes. Of these, 22 had hyperlipoproteinemia (HLIPR) by paper electrophoresis and by elevation of principal plasma lipids (either cholesterol over 300 mg/100 ml or triglycerides over 200 mg/100 ml or both these components). More than two-thirds of the patients had at least one close relative with elevated blood lipids. Using criteria of the World Health Organization, these patients were classified as follows: 5 had HLIPR type IIa, 8 had HLIPR type IIb, 3 had HLIPR type III and 6 had HLIPR type IV. Phospholipids showed relatively little change from the values of normal controls. The numerical distribution of patients with stroke and HLIPR into the four different types corresponds quite well with the approximate frequency of these types of HLIPR in the general population. Thus, this study does not indicate that the patients with a particular type of HLIPR are at a greater risk to have a stroke than those belonging to other types.