BACKGROUND: Along with the established effects of opium on metabolic parameters, stimulatory or inhibitory effects of opium on metabolic syndrome are also predictable. This study aimed to examine the association of opium use with metabolic syndrome and its components. METHODS: This study was conducted on 5332 out of 5900 original sample participants enrolled in a population-based cohort entitled the Kerman Coronary Artery Disease Risk Study in Iran from 2009 to 2011. The subjects were divided into three groups of “non-opium users” (NOUs = 4340 subjects), “former opium users” (FOUs = 176 subjects), and dependent and occasional people named “current opium users” (COUs = 811 subjects). Metabolic syndrome was defined according to two International Diabetes Federation (IDF) and National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) definition criteria. RESULTS: The overall prevalence of IDF defined-metabolic syndrome among NOUs, FOUs, and COUs was 36.4%, 27.3%, and 39.0%, respectively; which was significantly higher in the COUs group (P = 0.012). However, no significant difference was revealed across the three groups in prevalence of NCEP defined-metabolic syndrome (NOUs = 37.2%, FOUs = 30.1%, and COUs = 39.6%, P = 0.058). The odds for IDF defined-metabolic syndrome was higher in both COUs [odd ratio (OR) = 1.28, P = 0.028)] and FOUs (OR = 1.57, P = 0.045) compared with NOUs as the reference adjusting gender, age, body mass index, and cigarette smoking. However, the appearance of NCEP defined-metabolic syndrome could not be predicted by opium use. CONCLUSION: Opium use can be associated with an increased risk for metabolic syndrome based on IDF criteria and thus preventing the appearance of metabolic syndrome by avoiding opium use can be a certain approach to preventing cardiovascular disease.