A macroergonomics intervention consisting of flexible workspace design and ergonomics training was conducted to examine the effects on psychosocial work environment, musculoskeletal health, and work effectiveness in a computer-based office setting. Knowledge workers were assigned to one of four conditions: flexible workspace (n=121), ergonomics training (n=92), flexible workspace+ergonomics training (n=31), and a no-intervention control (n=45). Outcome measures were collected 2 months prior to the intervention and 3 and 6 months post-intervention. Overall, the study results indicated positive, significant effects on the outcome variables for the two intervention groups compared to the control group, including work-related musculoskeletal discomfort, job control, environmental satisfaction, sense of community, ergonomic climate, communication and collaboration, and business process efficiency (time and costs). However, attrition of workers in the ergonomics training condition precluded an evaluation of the effects of this intervention. This study suggests that a macroergonomics intervention is effective among knowledge workers in office settings.