The aim of this analysis was to compare levels of risk factors for coronary heart disease (CHD) in men and women aged 25-64 years between German-speaking MONICA collaborating centres, the German Democratic Republic (GDR), Augsburg - the Federal Republic of Germany (FRG)(Au), Bremen - FRG (Br), Heidelberg - FRG (He), and Vaud/Fribourg - Switzerland (CH, with a German-speaking minority). Prevalence of cigarette smoking in men showed little variation in four centres (34 to 40%) and was higher in BR men (49%), while it varied from 17% (GDR) to 33% (BR) in women. Mean total serum cholesterol values (mmol/L) were highest in GDR and CH men (both 6.2) and GDR women (6.1), and lowest in both He men (5.7) and He women (5.6). The proportion with cholesterol values greater than or equal to 6.7 mmol/L was largest in CH men (34%) and smallest in FRG (He) women (17%), while lowering the cut-off point from 6.7 to 6.5 mmol/L raised the prevalence of hypercholesterolaemia in all centres by 5 to 10%. Mean values (mmHg) of blood pressure (BP) were highest in both GDR men (140/88) and women (138/86), as was the prevalence of hypertensive BP values. In all centres, women aged 25-34 had BP values approximately 12/5 mmHg lower than age-matched men, but BP values similar to men at age 55-64, which indicates that age-parallel increase in BP was steeper in women than men.(ABSTRACT TRUNCATED AT 250 WORDS)