Nanjing and Nagoya of Japan became sister cities in 1978. They are the first pair of Sino-Japanese sister cities following the signing of the Sino-Japanese Peace Agreement, and are also the first pair of sister cities that Nanjing forged with a foreign city. Nanjing has since established sister-city relations with St Louis of USA, Florence of Italy, Eindhoven of the Netherlands, Leipzig of Germany, Limassol of Cyprus, Bloemfontein of South Africa, Daejeon of the Republic of Korea, Perth of Australia, London City of Canada, Mexicali of Mexico, Barranquilla of Colombia and Malacca of Malaysia. Nanjing so far has established sister-city relations with 13 foreign cities.

In recent years, Nanjing has organized a large number of exchange activities and carried out wide rang of exchanges and co-operation in such spheres as economy, trade, science and technology, culture, education and tourism. Among them, the 2006 China Nanjing World Historical and Cultural Cities Expo, China Nanjing Golden Autumn Economic and Trade Fair, China (Nanjing) International Software Product Expo, China Nanjing Plum Blossom Festival and China Yangtze River International Tourism Festival have already become famous activities in foreign exchanges.