Pedometer-determined physical activity (PA) levels in Belgian adults were provided and compared to PA scores reported in the International Physical Activity Questionnaire (IPAQ). The representative sample (N = 1,239) of the Belgian population took on average 9,655 (4,526) steps/day. According to pedometer indices 58.4% were insufficiently active. Steps/day differed significantly between gender (F = 5.0, p = 0.026), age groups (F = 3.3, p = 0.01), employment status (F = 6.2, p = 0.013), and days of monitoring (F = 7.4, p = 0.007). Steps/day were negatively correlated to the time spent sitting and positively to PA at work, in transport, and in leisure time (p less than 0.001). Steps data can discriminate between PA levels reported in the IPAQ. Belgian population pedometer-determined PA levels are higher than those reported in samples of the United States; however, there is a wide distribution of ambulatory behavior. (Contains 1 figure and 2 tables.)