The discussion in this paper is based on the findings of a study supported by the King's Fund and conducted under the auspices of the Royal College of Radiologists Working Party on the Effective Use of Diagnostic Radiology in which four strategies were evaluated for implementing guidelines on the use of pre-operative chest X-rays. The paper discusses the need for strategies; the process of developing guidelines; and how strategies may be implemented. Containing the use of diagnostic tests is discussed within the context of the financial, organisational and attitudinal constraints within the NHS. Some recommendations are made on how unit managers and clinicians might initiate change to contain the use of diagnostic services in NHS hospitals.