Corporate diversification has become an integral part of the strategy of many publishing companies. These diversification strategies may include both product diversification and international geographic diversification. This study demonstrates the diversification strategy of large-sized publishing companies. A number of measures and techniques are used to measure the diversification of these companies. We construct an additional measure to show the international diversification of the publishing companies. The findings indicate the existence of a set of common underlying dimensions or factors between a few measures, although no evidence of unidimensionality amongst all diversification measures exists. The various diversification indicators measure different aspects of diversification of publishing companies. Our data show that the publishing companies diversify into related activities and businesses and that, in particular, north american publishing companies do not diversify internationally.