Andrea Palladio’s Church of the Redentore (1577–1592) in Venice is one of his greatest achievements, and a masterpiece of the Italian High Renaissance. Despite the considerable body of Palladio scholarship, there is relatively little research focused on the design of his churches. A laser-assisted survey was recently undertaken at the Redentore, measuring the significant dimensions and calculating the proportional relationships that define the interior spaces of the church. These proportional ratios are those Palladio cites as his preferred ratios in Book I of his Quattro Libri, and those marked on his illustrations of villa plans in Book II. The survey findings made it possible to suggest a sequence of steps by which Palladio could have developed his design for the whole church. The total interior length and the transept width were determined by the available site; they were likely the basis from which the other dimensions were generated, through a series of interconnected proportional ratios. The plan dimensions could have determined the vertical dimensions of the elevation. The width/length/height relationships conform to Palladio’s methods to determine the height of vaulted rooms. The study found significant evidence that Palladio was influenced equally by the prescriptions of Vitruvius and Alberti, and the mathematical and geometrical procedures of traditional medieval design. Palladio’s design for the Redentore suggests that the division between the Gothic and Classical styles in Italian High Renaissance architecture is less absolute than has previously been supposed.