Objectives: The aim of this study was to examine the multi-instrument assessment of physical activity in female office workers. Material and Methods: Fifty healthy women (age (mean ± standard deviation): 34.8±5.9 years, body height: 158±0.4 cm, body weight: 61.8±7.5 kg, body mass index: 24.6±2.7 kg/m²) workers from the same workplace volunteered to participate in the study. Physical activity was measured with the 7-day Physical Activity Assessment Questionnaire (7-d PAAQ), an objective multi-sensor armband tool, and also a waist-mounted pedometer, which were both worn for 7 days. Results: A significant correlation between step numbers measured by armband and pedometer was observed (r = 0.735), but the step numbers measured by these 2 methods were significantly different (10 941±2236 steps/ day and 9170±2377 steps/day, respectively; p < 0.001). There was a weak correlation between the value of 7-d PAAQ total energy expenditure and the value of armband total energy expenditure (r = 0.394, p = 0.005). However, total energy expenditure values measured by armband and 7-d PAAQ were not significantly different (2081±370 kcal/ day and 2084±197 kcal/day, respectively; p = 0.96). In addition, physical activity levels (average daily metabolic equivalents (MET)) measured by armband and 7-d PAAQ were not significantly different (1.45±0.12 MET/day and 1.47±0.24 MET/day, respectively; p = 0.44). Conclusions: The results of this study showed that the correlation between pedometer and armband measurements was higher than that between armband measurements and 7-d PAAQ selfreports. Our results suggest that none of the assessment methods examined here, 7-d PAAQ, pedometer, or armband, is sufficient when used as a single tool for physical activity level determination. Therefore, multi-instrument assessment methods are preferable. Int J Occup Med Environ Health 2016;29(6):937–945