Objective In order to estimate the prevalence of metabolic syndrome (MetS) as defined by NCEP Adult Treatment Panel III (ATP III) criteria in the Trabzon Region and its associations with demographic factors (age, sex, marital status, reproductive history in women, and level of education), socioeconomic factors (household income and occupation), family history of selected medical conditions (diabetes, hypertension, and obesity), lifestyle factors (smoking habits, physical activity, and alcohol consumption) in the adult population. Research Methods and Procedures In this cross-sectional survey, a sample of households was systematically selected from the central province of Trabzon and its nine towns. A total of 4,809 adult subjects >= 20 years (2,601 women and 2,208 men) were included in the study. Blood pressure levels were measured for all subjects. The persons included in the questionnaire were invited to the local medical centers for blood examination between 08:00 and 10:00 following 12 h of fasting. Fasting serum glucose (FBG) levels and lipid profile were measured with autoanalyzer. MetS was defined according to guidelines from the NCEP ATP III diagnostic criteria. Results The prevalence of MetS was 26.9%: 31.3 in women and 21.7% in men. The prevalence increased with age, being highest in the 60-69-year-old age group (53.4%) but lower again in the >= 70 age group. MetS was associated positively with marital status, parity, cessation of cigarette smoking, and negatively with the level of education, alcohol consumption, current cigarette use, household income, and physical activity. Hypertension was found as the most common MetS component in our study (57.4%). Others in decreasing order were abdominal obesity (40.9%), low high-density lipoprotein-C (HDL-C) (31.8%), hypertriglyceridemia (30.7%), and high FBG levels (9.2%). Similarly, in the subjects diagnosed with MetS, HT had the highest prevalence (91.9%). This was followed by abdominal obesity (82.3%), hypertriglyceridemia (74%), low HDL-C (68.6%), and high fasting blood glucose levels (28.6%). Discussion MetS is moderately common and an important health problem in the adult population of Trabzon. In order to control MetS and its components, effective public health education and taking urgent steps are needed. These steps include serious education, providing a well-balanced diet and increasing physical activity.