In the study of international relations in the post-war period two major areas of concern have been identified: the confrontation between the United States and the Soviet Union, and the gulf between wealthy and poor states. Associated with the latter is the phenomenon of decolonisation. Marxists, Western scholars, and other structuralists have all contributed to divergent analytical frameworks for analysing the relationship between decolonisation and imperialism. The principal disjuncture centres on whether or not imperialism ends with decolonisation. Time series analysis and the quasi-experimental interrupted time series design, in particular, are employed to test the theoretical perspectives, using the New Zealand example. Having outlined New Zealand's experience as a colonial power, cultural and economic imperialism are selected as variables and indicators are developed for them. Data are collected and analysed, with the result that New Zealand maintains its economic relationship with its former colonies after independence, but cultural imperialism declines. The results are used to assess both the implications for New Zealand and its relationship with Western Samoa, the Cook Islands and Niue, and for each of the theoretical perspectives. Finally, areas of potentially valuable research are identified as are the likely limitations imposed through lack of data, and inconsistency of data when dealing with several cases. The question II the end of imperialism?" is deserving of more research.