This paper focuses on Galen’s views about the formal cause against the wider background of his account of causation. In his works on the pulse, Galen provides an in-depth discussion of issues such as the theory of causes and the problem of definition. While Galen is inclined to incorporate Peripatetic doctrines and vocabulary, he neglects Aristotle’s formal cause both in his account of causes and in that of definition. Further parallels outside the corpus on the pulse confirm Galen’s reserved attitude (...) towards the (Peripatetic) formal cause. In his work That the Faculties of the Soul Follow the Mixtures of the Body, however, Galen refers favourably to the Peripatetic theory of hylomorphic form. More precisely, Galen equates the Peripatetic en-mattered form with the mixture of homoeomerous bodies (the ratio or proportion of the elementary qualities in them). Here I will attempt to provide an explanation of Galen’s mixed attitude towards the formal cause and I will argue that his general position is consistent after all. In addition to this, I will try to set Galen’s position against the background of the Peripatetic debates on the status of form. (shrink)