Why have large numbers of the Bajju people of the Middle Belt of Nigeria become Christians? The first conversions occurred in 1929 and today almost one hundred percent of the Bajju claim to be Christians, so this people movement happened within a relatively short period. McKinney details the various contexts in which religious change took place among the Bajju: in traditional Bajju culture, in their relations with the Hausa-Fulani, in the British colonial context, and in the missionary context. She presents the results of an in-depth interview schedule administered in 1984 and 2011 to respondents in both a rural village and a Kaduna suburb. This longitudinal study, together with the author's involvement in participant observation, personal language learning, and archival records research, help provide answers to the questions of why, and to what degree, a worldview paradigm shift has occurred among the Bajju. The author also discusses some traditional religious beliefs retained by Bajju Christians, and charts traditional religious beliefs with biblical texts. Bajju Christian Conversion in the Middle Belt of Nigeria will be essential to anthropologists specializing in conversion studies, and be of interest to missiologists, and to the Bajju people themselves. It is a companion volume to Baranzan's People: An Ethnohistory of the Bajju of the Middle Belt of Nigeria, published by SIL International® 2019.