This publication describes strategies for improving the effectiveness of in-service inspection (ISI). The role of ISI in maintaining or improving safety and the relationship of ISI improvement to cost are examined. The strategies for improving ISI effectiveness discussed in this publication consider the entire framework of ISI, including effective selection of the proper scope of inspection and the effectiveness of non-destructive examination as demonstrated through inspection qualification programmes. Improving the effectiveness of ISI in an economical and organized way requires adoption of a strategy that meets the specific objectives of each plant owner. Several such strategies are considered.