The sixteenth-century Cathedral of Goa and the Jesuit church Bom Jesus reflect mainly European architectural concepts, before local influences appeared in the Portuguese Christian architecture of the following centuries. The research presented here investigated the use of proportional systems. The results show that both the Cathedral and the Bom Jesus have proportions that are usually found in Renaissance architecture of their time, namely, the “ad quadratum” progression and the use of a 4:3 rectangle.