Evidence is growing on adverse health outcomes associated with less physical activity (PA) and more sedentary behavior (SB). As most workers generally spend approximately one-third of the day at work, measuring the amount of occupational PA/SB time would contribute to understanding the health risks of physical inactivity and SB among workers. In this review article, we describe the amount of time spent in different intensities of activity (moderate-to-vigorous PA [MVPA]; light PA [LPA]; and SB), on work and non-work days, while at work and outside working hours among workers. The review used objective measurements made by an accelerometer and showed the proportion of MVPA that office workers engaged in on work and non-work days accounted for 3-5% and 2-4% of accelerometer wear time, respectively. Moreover, office workers spent more time in SB and less time in LPA on work days than non-work days (SB, 66-76% vs. 60-69%; LPA, 20-28% vs. 23-36%). Especially on work days, office workers spent the greatest proportion of the day in SB during working hours (71-82%), compared with that outside working hours (63-67%). The proportion of MVPA accounted for 2-5% during working hours and 3-7% outside working hours. In addition, there were considerable differences in the proportions of LPA and SB between white-collar and blue-collar workers during working hours (SB, 73 vs. 55%; LPA; 22 vs. 40%), whereas the MVPA time was similar (5 vs. 5%). Some occupational exposure to unfavorable PA/SB at work might be unavoidable; however, inadequate PA/SB during working hours should be corrected.