That a certain principle pervades the whole of the Dionysian corpus has been commonly acknowledged by readers of the works of this intriguing author. The principle is that of participation, which frames the structure of Dionysian thinking in all its aspects, the Christological, the liturgical and ecclesiological as well as the ontological. Most schol- arly studies of this Christian, nonetheless Neoplatonic, figure mostly recognize the participatory character of his thinking. In his participatory metaphysical system there is a feature that seems (...) to be crucial. Except for some sporadic remarks – few in relation to the huge number of relevant studies – and in spite of the influence exercised on the thought of Maximus the Confessor and Thomas Aquinas, this feature has not received the attention that its centrality merits. I refer to the concept of aptitude (ἐπιτηδειότης). In the present study I explore aptitude as a critical component of the Dionysian devel- opment of participation, with a view to the Neoplatonic background of the concept, especially as established by Plotinus and Proclus. My aim is to argue for a novelty consisting in the fact that the Areopagite regards aptitude as a fundamental element that sets forth the receptive capacity of beings as the regulatory principle for participation in the life of the divinity. -/- +++ -/- This paper expands over certain ideas presented in a short communication, during the Seventeenth International Conference on Patristic Studies held in Oxford 2015. It explores the concept of aptitude (ἐπιτηδειότης) as a critical component of the Dionysian development of participation, with a view to the Neoplatonic background of the concept, especially as established by Plotinus and Proclus. The aim of the study is to argue for a novelty consisting in the fact that the Areopagite regards aptitude as a fundamental element that sets forth the respective capacity of beings as the regulatory principle for participation in the life of divinity. (shrink)