This paper focused on the examination of the evolution of the Sukuma marriage conduct in the traditional setting and the influence which the Roman Catholic Church exerted on the Sukuma traditional marriage practices. The different forms and procedures of traditional marriages practiced among the Sukuma before the introduction of Christianity in the nineteenth century are explored. Several studies had been conducted on how traditional marriage institutions among the Sukuma were sustained despite the penetration of Christianity. Others investigated on how Christianity of different denominations in general affected the Sukuma marriage practices. This study, therefore, focused on how the Roman Catholic Church influenced the Sukuma traditional marriage. Despite its strong roots in Magu district none of the studies investigated its influence on traditional marriage institutions. A historical research methodology was employed in which different historical sources both primary and secondary were visited. Secondary sources were collected through a review of documents from libraries and different resource centers. The bulky primary information was accessed from archival sources. The existing oral histories kept by local Sukuma historians were accessed by visiting their custodians. The data generated revealed that the coming of Roman Catholic Church and the subsequent introduction of Christianity among the Sukuma introduced Christian marriage which threatened the existence of Sukuma traditional marriages. Currently, many Sukuma goes for Christian marriage and traditional marriages are seen as old-fashioned. But the Roman Catholic Church destroyed these very veins of the Sukuma society. Consequently, the Sukuma society started losing grip of the attributes that consolidated the society as a single whole.