The present report is a description of the characteristics of a studied population and of the methodology used in a study performed to investigate high blood pressure prevalence and cardiovascular risk factors among the adult population of Mexico City. A cross-sectional study was conducted from January 1991 to March 1992. Random samplings of multiple stages was used and 825 adult subjects were studied in Mexico City. The following measurements were registered: blood pressure, body mass index (BMI), waist-hip ratio (WHR), total cholesterol (TC), triglycerides (TG), high density lipoproteins (HDL-C) and low density lipoproteins (LDL-C), lipoprotein (a) (Lp(a)), glucose and insulin. Personal and family history of cardiovascular illness were investigated, as well as exposure to some risk factors such as smoking, alcohol consumption and sedentarism. The response rate was 86.6%. The prevalence of high blood pressure was 21.1%, and of non-insulin dependent diabetes mellitus was 8.7%. Frequency of dyslipidemia in the studied sample was 24.4% for high TG, 23.6% for low HDL-C, 23.6% for high LDL-C, 14.9% for Lp(a) excess (Lp(a) > or = 30 mg/dl; overweight and obesity were more prevalent among women. The diversity of living conditions among the population of Mexico City was included in the sampling strategy design, not only to register the high blood pressure (HBP) frequency in each stratum but to identify other cardiovascular risk factors which could be decisive in the development of HBP. Regarding the features of the studied population, BMI did not reveal differences among men, but their TG levels were higher and HDL levels lower than those of other populations. In women, the results obtained for BMI, WHR, lipids and lipoproteins were also higher compared with the mean reported for other populations.