Background: Obesity is one principle risk factor increasing the risk of noncommunicable diseases including diabetes, hypertension and atherosclerosis. In Thailand, a 2014 study reported obesity (BMI ≥25 kg/m 2) in a Thai population aged ≥15 years was 37.5, 32.9 and 41.8% overall and among males and females, respectively. The study aimed to determine trends in the prevalence of obesity among adults residing in a Thai rural community between 2012 and 2018 and investigate the associations between obesity and behavioral factors. Methods: Serial cross-sectional studies were conducted in 2012 and 2018 among adults in Na-Ngam rural community. In 2012 and 2018, all 635 and 627 individuals, respectively, were interviewed using structured questionnaires related to demographics, risk behaviors, comorbidities and arthrometric measurement. Spot urine was collected by participants and obesity was defined as BMI ≥25 kg/m 2. The risk factors for obesity were analyzed in the 2018 survey. Results: A total of 1262 adults in Na-Ngam rural community were included in the study. The prevalence of obesity was 33.9% in 2012 and 44.8% in 2018 (P < 0.001). The average BMI increased from 23.9 ± 4.2 kg/m 2 in 2012 to 25.0 ± 4.52 kg/m 2 in 2018 (P < 0.001). Obesity was associated with higher age (AOR 0.99; 95%CI 0.97-0.99), smoking (AOR 0.52; 95%CI 0.28-0.94), instant coffee-mix consumption > 1 cup/week (AOR 1.44; 95%CI 1.02-2.04), higher number of chronic diseases (≥1 disease AOR 1.82; 95%CI 1.01-2.68, > 2 diseases AOR 2.15; 95%CI 1.32-3.50), and higher spot urine sodium level (AOR 1.002; 95%CI 0.99-1.01).