The recent diversity of ethnic and religious backgrounds of people in Hammarkullen led to a merger between the Evangelical Lutheran church of Sweden and Swedish Mission Covenant church, leaving the Hammarkullen church empty. This paper presents the transformation and conversion of Hammarkullen church into a music school for the program El Sistema, an orchestra program for children. Through research and analysis of the church and the surroundings areas, including the existing facilities of El Sistema in Hammarkullen, a viable proposal was designed. The proposal takes into account from an early stage the acoustic requirements which have had substantial impact on the design. To better accommodate the new function, the church annex was demolished and a new building is added in its place where the rehearsal rooms are located. The church building also suffered some structural changes and an extension was needed to better suit a concert hall. The intervention should increase the area both culturally and economically.