The creation of agencies has been and still is a widespread trend in the public sector: governments in many countries often establish semi-autonomous single-purpose organizations to carry out a wide range of functions and tasks. The trend to autonomization is problematic as it affects public sector's governance: several bodies operate partly autonomously from the core elective government, and are sometimes loosely coupled with their ‘parent’ administration. Consequently, analysing the drivers of agencies’ autonomy is a crucial issue for public management. This paper, in the light of some major contributions in organizational science, assumes that agencies’ autonomy is influenced by factors that affect post-delegation relationships: agencies’ structure, culture and nature of the tasks executed. The study was aimed at testing a range of hypotheses about the autonomy of public agencies, using for this purpose the so-far not investigated case of Italy–much in the spirit of the accumulation of knowledge in an area of public management. Results do not provide any strikingly counter-intuitive finding, but a mix of confirmations and disconfirmations of previous findings that allow a finer-grained analysis on the determinants of agency autonomy.