A high standard of integrity is demanded of the steam generator tubing in nuclear power stations to minimise the cost of any loss of availability due to a need for repairs or plugging. If any deterioration should occur it is desirable to identify it before failure in order to permit preventive maintenance to be considered and, particularly for prototype plant, provide early guidance as to the possible need for changes in the design of later plant. These requirements have resulted in the continuing development of inspection techniques for application at the fabrication stage and subsequently in-service. For the latter it is desirable that inspections do not extend the length of shutdowns beyond that required for core refuelling and routine maintenance and the associated statutory plant inspections. The above needs apply to all reactor types but the in-service inspection undertaken is very much affected by the type of plant and the available operating experience with similar units. Thus the acceptable leak rate between sodium and water in the fast reactor steam generator is measured in grammes per hour while kilogrammes per hour would be a more appropriate unit for PWRs. For the latter there is an additional requirement to lower the radiation exposure during inspection. This paper discusses reported European developments in the field and concentrates on the problems of inspecting the tubing and tube-to-tubeplate joints. Also, although the ultimate integrity of a plant unit is dependent on the quality of the original fabrication with its associated inspection, most attention is given to ISI. Apart from the continuing development of eddy current techniques for austenitic tubing, the past five years have seen an increasing interest in ultrasonic techniques for detailed tubing examination while digital data handling has been demonstrated in the field. In the fast reactor area the development of improved NDT procedures for both fabrication and ISI of explosive welds is helping to provide the basic technological know-how which is essential if explosive welding is to be considered as a serious design option for large scale application for the tube-to-tubeplate joints in large steam generators.