Sometimes referred to as Safe Operating Procedures, Safe Systems of Work (SSOW) are formal procedures which define the safe methods and procedures that need to be adopted during work activities to ensure that hazards are eliminated and risks minimised. They are used to control work activities and they ensure that the work tasks are carried out in a safe and healthy manner. They will form the basis of task related training for both workers and supervisors and will usually be established following a risk assessment.

A SSOW is not an alternative to taking other legally required precautions such as providing well-maintained, physical safeguards. There are some situations where these physical precautions alone will not give adequate protection. For example, maintenance and repair work often involves the removal of guards or other physical protection. During lifting operations the load may be well within the capacity of the crane but unless the load is properly attached according to a SSOW it could become unstable and be the cause of an accident.

A SSOW can take a number of different forms and may be referred to as job safety instructions, safe working procedures or method statements.