A new two-dimensional video-based technique for the recording and analysis of working posture has been developed and applied to seated work. After initial set-up of the portable equipment in the workplace, and attachment of small adhesive retroreflective joint markers on the subject, an operator is not required for the remainder of the recording session. Analysis of the video recording is conducted in the laboratory using custom-written software and a commercially available image-processing package running on an IBM AT-compatible computer. After interactive set-up of a reference frame, the system is able to analyse the full video tape automatically, extracting video frames for analysis at approximately 30-s intervals. Poor image quality may occasionally necessitate interactive analysis. The system is capable of determining postural angles to an accuracy of 1-2 degrees , and thus represents a substantial improvement on other postural analysis systems which are able to be used readily in the workplace.