Catholic religious music plays an important role in Christian worship and spiritual formation in Rwanda, where biblical faith is expressed through local languages, cultural values, and musical traditions. This study, entitled From Biblical Psalms to Catholic Religious Songs: Exploring the Role of Catholic Religious Music in Christian Spiritual Growth in Rwanda, examines the relationship between the biblical Psalms and Catholic religious songs and their contribution to Christian spiritual growth. The study asks: How does Catholic religious music contribute to prayer, faith formation, personal conversion, Christian identity, and participation in communal worship? It hypothesizes that Catholic religious music enhances Christian spiritual growth when its biblical and theological content is faithfully expressed through culturally meaningful forms. The objective is to examine this relationship and assess the role of Catholic religious music in Christian formation and evangelization. A descriptive mixed-methods design was employed among 70 undergraduate students of the Faculty of Theology at the Catholic University of Rwanda (CUR). Data were collected through structured questionnaires and analyzed using descriptive statistics and thematic analysis. Findings indicate that 95.7% of respondents viewed religious music as an aid to prayer, 94.3% associated it with spiritual growth, 92.9% emphasized biblical foundations, 91.4% perceived it as effective for faith formation, and 90.0% reported increased participation in communal worship. The study concludes that Catholic religious music is a valuable instrument of Christian formation and evangelization.