The development and applications of activation analysis in the period 1945–1980 are reviewed. In analysing the number of publications reported with time three periods can be distinguished: (a) A first period of slow development, up to 1960, in which the technique showed its very high sensitivity and demonstrated the importance of trace elements; (b) A second period of fast development (1960–1970) in which all aspects of the technique were developed; (c) A third period (after 1970) in which development occurred at a rate approximately equal to the average development rate of analytical chemistry, in terms of the number of publications reported. The present trends shows only minor developments in the methodology, while a good a potential for new and original applications is evident. The importance of a good scientific knowledge of the specific areas of applications is considered necessary to properly frame the analytical activities.