Office-based workers typically have a sedentary lifestyle and spend the majority of their working hours sitting, which can lead to an increased risk of cardiometabolic diseases. This cross-sectional study aimed to quantify sedentary behavior and overall physical activity, and to determine their association with cardiometabolic risk factors in a cohort of 122 office workers. Sedentary behavior and physical activity were assessed using questionnaires and wrist-worn Axivity accelerometers. Weight, height, body mass index, waist circumference, waist-to-height ratio, blood pressure, and point-of-care blood variables (namely, lipids and lipoproteins, glucose, and glycated hemoglobin) were also measured. Most (68.0%) of the study participants were women, with a mean age of 40.2 +/- 9.3 years. The self-reported total daily sedentary time for this cohort was 595.5 min/day (IQR: 413.5-863.4 min/day). Accelerometry-measured sedentary behavior was positively associated with light physical activity (beta: .98, P = .001) and inversely associated with moderate-to-vigorous activity (beta: -.08, P = .01). Both systolic (beta: -.234, P = .037) and diastolic blood pressure (beta: -.250, P < .001) were inversely associated with accelerometry-measured light physical activity. However, there was no association between sedentary behavior and cardiometabolic risk factors. Our findings show that South African office workers spend a substantial amount of time sitting during work hours and while commuting, and support the need for public health workplace interventions to mitigate the potential health risks of sedentary behavior.