Based on extensive field work and critical literature review, this paper examines four and a half centuries of Catholic heritage in Nagasaki with its distinctive churches built in its countryside since the late nineteenth century. These buildings are now our focus of attention because of their application as UNESCO World Heritage Sites, which will naturally lead to becoming attractive spots for tourists in the future. With its Catholic heritage, Nagasaki Prefecture has as many as 137 churches throughout its peninsulas and islands, 13% of the 1,006 churches in Japan. You might wonder why this is. Actually, Christianity was first introduced by St. Francisco Xavier in 1549, and missionaries active mainly in Nagasaki and neighboring areas in the latter half of the 16th century. However, in 1614, the Tokugawa shogunate banned the religion. As a result, many Christians went underground, with some nominally converted to Buddhism without losing their Catholic faith, thus having dual funeral services. They were kakure kirishitans (Christians) hiding themselves from the mainstream of the local communities. They lived mostly in the Nagasaki area including Nagasaki, Urakami, Sotome, Hirado, Ikitsuki, and the Goto archipelago. Later, their practice became a form of folk religion. After gaining freedom of religion in 1873, many kirishitans came out with their firm faith, and began building churches in their communities. They were usually planned by the French priests in collaboration with Japanese architects, and assisted by a workforce of local Catholic followers. In this respect, such names as Father Marc-Marie de Rotz (1840〜1914) and Yosuke Tetsukawa (1879〜1976) are notable and worth remembering. The churches' styles and building techniques were blend of French Neo-Romanesque or Neo-Gothic with traditional Japanese architecture. The materials used evolved in three stages : wooden, brick/ stone, and reinforced concrete. These churches often include such elements as ribbed vaults, carved capitals with acanthus-leaf decoration, floral stained glass, Lombard bands, and bell towers. With this rich Catholic tradition, Nagasaki's churches and related monuments such as kirishitan sanctuaries and castle ruins are recommended as the World Heritage Sites for the year 2016. On the proposed list of Cultural Heritage locations are five of some fifty churches built by Tetsukawa : Former Nokubi Church, Kashiragashima Church, Egami Church, Tabira Church, and Sakitsu Church. The local Catholic communities would certainly feel much to pride for their faith and heritage. Nevertheless, the increasing number of pilgrims and tourists to the peninsulas and islands, particularly the Goto archipelago, might create many challenging issues that need to be resolved : maintaining church architecture and other related monuments, improving marine and land transportation systems, and preparing enough accommodations and public facilities to meet the expected increased demand of visitors. Finally, let me note that this research work is supported by the Kyodo Kenkyu Project at Momoyama Gakuin University for the period April 2011 to March 2014. The title of the project is `Topography of Nagasaki in the Japanese History of Intercultural Adaptation and Exchange: From a New Perspective of Global History".