The article aims to investigate the Calvin’s Genevan Service Order. It focuses on the question how the Psalter Calvin shaped the worship of the Reformed Church in Geneva. The article follows the critical edition of the Genevan prayer in Calvini Opera Selecta and in the German Studienausgabe as the two main published editions of the Genevan order with its related texts. The article shows that Calvin adhered to the general line of the Swiss and Upper German Reformations. It explores the understanding of worship reflected in the Genevan Service Order and the specific significance of its musical aspect. The article illustrates why Calvin gave the psalms the place he did in Genevan Reformed worship.