Demands for increased productivity despite cuts in financial resources have renewed the discussion of cost effectiveness in medical care. Unfortunately, there is a lack of reliable data for evaluating the cost effectiveness of diagnostic procedures. The present article discusses various aspects of this topic and presents examples from the diagnostic evaluation of the upper abdomen. It is argued that modern imaging procedures have in the past helped to reduce costs and that they can become cost effective when they replace established combinations of diagnostic procedures. The present discussion is severely hampered by the fact that there are no generally accepted standards for evaluating diagnostic strategies and that there are no well-founded studies of the cost effectiveness of the strategies used in abdominal diagnosis. Cost effectiveness will in the future become an additional criterion for assessing the quality of medical care.