Background Single-port access video-assisted thoracic surgery (VATS), a technique progressively developed from the standard three-port approach in minimally invasive surgery, offers ergonomic advantages but also new challenges for the surgeon. We compared the ergonomics of three-port versus single-port VATS. Methods Posture analysis of surgeons was evaluated during 100 consecutive VATS wedge resections (50 triportal vs. 50 uniportal). Technically demanding procedures (major lung resection) were excluded. Operating table height, monitor height, distance and inclination were adjusted according to operator preference. Body posture was assessed by measuring head–trunk axial rotation and head flexion. Perceived physical strain was self-evaluated on the Borg Category Ratio (CR-10) scale. Mental workload was assessed with the National Aeronautics Space Administration–Task Load indeX (NASA–TLX), a multidimensional tool that rates workloads on six scales (mental, physical and temporal demand; effort; performance; frustration). Results All procedures were completed without complications. Head–trunk axial rotation was significantly reduced and neck flexion significantly improved in uniportal VATS. Viewing direction significantly declined ( p  = 0.01), body posture as measured on the Borg CR–10 scale was perceived as more stressful and the NASA–TLX score for overall workload was higher ( p  = 0.04) during triportal VATS. The NASA–TLX score for frustration was higher with uniportal VATS ( p  = 0.02), but the score for physical demand was higher in triportal VATS ( p  = 0.006). Conclusions The surgeon can maintain a more neutral body posture during uniportal VATS by standing straight and facing the monitor with only minimal neck extension/rotation; however, frustration is greater than with triportal VATS.