This is a study of the relationship between music and spirit possession among the YorÃ¹bÃ¡ of the South-Western part of Nigeria. Through the ages, philosophers and scholars have been interested in the relationship between music and trance possession, especially the question of whether music triggers, influences or sustains trance or spirit possession, and if so, how. This thesis seeks to focus on the relationship between the music used in worship practices where possessions take place, and how the music might initiate and drive the possession states. Spirit possession is a phenomenon which springs from and is associated with the social and belief systems of different people. However, the AlÃ¡durÃ church (an Independent African Church â AIC) worshippers dissociate themselves from the possession practices that are experienced among the YorÃ¹bÃ¡ indigenous traditional worshippers, while the traditionalists claim that the spirit possession practised in the AlÃ¡durÃ churches originated and has its roots in the traditional practices. This suggests an inherent difference in the two belief systems even though the possession experiences among them are characterised by similar presentations. Following the theory that spirit possession practices are culturally determined, this research seeks to identify the specific cultural elements in the music used in YorÃ¹bÃ¡ worship traditions where possessions take place, not as a cause and effect, but how music affects the possession process. My study, therefore, sets out to investigate what could be a common factor between the two structurally and contextually different types of music used by the two sects of worshippers with the aim of identifying the common factors in the music, which seem to be the link between the two worship groups. Key words: Music, Spirit Possession, culture, worship.