Introduction: This study aimed to ascertain the effects of a Facebook-based physical activity intervention on improvements in step counts and metabolic syndrome. Methods: Government employees with metabolic syndrome were randomly assigned by cluster to the Facebook group (n = 44) or the control group (n = 103). All participants were asked to complete self-administered questionnaires at baseline, after the first and second phases. Data from anthropometric (weight, body mass index, fat mass, body fat percentage, waist circumference, hip circumference and waist-to-hip ratio), biochemical (total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides and fasting glucose) and clinical examinations (systolic blood pressure and diastolic blood pressure) were collected. The number of steps per day was determined by a Lifecorder e- STEP accelerometer. Results: A significant difference in the number of steps per day between the baseline and the first phase (p