This document discusses principles and phases of preventive action for occupational safety and health (OSH). It outlines key international conventions and directives on OSH, including establishing national OSH policies, providing guidance to employers and workers, and including OSH training at all education levels. The principles of risk evaluation, preventive planning, and organizing adequate resources like qualified OSH staff are explained. Effective inspection and monitoring systems require upgrading institutions, training staff, coordinating between organizations, and developing OSH tools. A successful process involves commitment from all concerned parties.