The aim of this study was to determine the prevalence of thyroid dysfunction and its association with cardiovascular risk factors in an adult Bulgarian population. 2402 subjects were studied, 1347 female, 20–94y (median: 48.0y) and 1055 male, 20–91y (median: 45.5y). Body weight, height, waist circumference, arterial blood pressure, TSH, FT4 and lipids were measured. Known hypothyroidism was reported by 53 subjects (2.2%) and hyperthyroidism by 20 (0.8%). New hypothyroidism was found in 98 (4.1%), [subclinical (3.2%), overt (0.9%)]. New hyperthyroidism was found in 68 (2.9%), [subclinical (2.5%), overt (0.4%)]. New diagnosis of hypothyroidism and hyperthyroidism was entered in 84% and 87% in male subjects and 60% and 65% in the females respectively. Arterial hypertension was present in 40% of the women and in 47% of the men (p<0.001) and was more prevalent in hypothyroidism. Abdominal obesity and dyslipidemia were more prevalent in males and hypothyroid subjects. Arterial hypertension depended on age, gender and lipid status but not on thyroid function. CHD history depended on thyroid function and age. Conclusion: Most cases of thyroid dysfunction were undiagnosed, especially in the males. CV risk factors were more prevalent in the males with thyroid dysfunction a major determinant of CHD, but not hypertension.