Erasmus’ Novum Testamentum of 1519 is an improved and enlarged edition of his Novum Instrumentum of 1516. The chief component remained his new version of the NT in more cultivated Latin than that of the Vulgate. But the 1519 edition also includes several Greek paratexts not yet printed in 1516. This article discusses the Greek witnesses which were used for the new edition and points out Greek and Latin readings in which it differs from 1516. The importance of the 1519 Novum Testamentum is that it constitutes the consolidation of Erasmus’ humanistic programme for promoting the study of the NT as an essentially philological discipline. The work is Erasmus’ self-confident vindication of this programme against advocates of the Vulgate and scholastic theology.