In 1525, a Catholic Book of Hours in Swedish (later called Den svenska tideboken) was printed in Uppsala, in the very same printing house that would issue the first Swedish translation of the New Testament in 1526. Whereas the latter, along with the other translations of biblical texts of the Lutheran reform, has been a frequent subject of philological research, the former has rather been regarded as a less intresting example of the linguistic decay of the pre-reform era, as the 19th century editor Klemming puts it. This paper examines three features of the language in the 40 psalms found in Den svenska tideboken, in comparison with the reform Psalter of 1536: the infinitive, the genitive and the word order in subordinate clauses and in infinite verb phrases. As to the infinitive and to orthography in general, it is clear that Den svenska tideboken shows a significant number of variation, while the 1536 Psalter is both more consistent and more faithful to the Old Swedish system. On the other hand, the genitive and the word order in Den svenska tideboken could be described as more faithful to the older system. There are also significant differences whithin Den svenska tideboken that deserve to be the subject of further research.