Introduction. Obesity is frequently associated with risk factors for cardiovascular and metabolic diseases. Central obesity is a marker of increased intra-abdominal adiposity and a known risk factor for atherosclerosis and diabetes; it is also a good predictor of risk for coronary events, cardiovascular mortality, diabetes and metabolic syndrome. A less predictive alternate measurement is known as the body mass index (BMI).Objective. Obesity prevalence was estimated first by BMI and then by abdominal obesity (measuredby waist circumference, WC) in primary care patients.Materials and methods. As part of an international study, primary care physicians recruited consecutive patients aged 18 to 80 years who consulted for any reason on two pre-specified half-days. Age, gender, smoking status and history of cardiovascular disease or diabetes were recorded. Height, weight and WC were measured using standard methods. Pregnant women and subjects unwilling to participate were excluded.Results. A total of 3,795 patients from 105 primary care centers located throughout Colombia were evaluated. The mean age was 45 years (69% females). Of these, 60.7% of males and 53.9% of females were overweight or obese according to their BMI; 24.6% of males and 44.6% of females had abdominal obesity when National Cholesterol Education Program guidelines were used, but numbers changed to62.5% and 67.0% when the International Diabetes Federation guidelines were used. Obesity, either determined by BMI or by WC, was associated with higher prevalence of diabetes, hypertension and dyslipidemia.Conclusions. Increased waist circumference is a practical and useful marker for cardiovascular and metabolic conditions. The prevalence of abdominal obesity in Colombian primary care patients is highand more frequent in females. doi: http://dx.doi.org/10.7705/biomedica.v32i4.799