Past participles (ending with -n (-an, -en), and -t) and the group of adjectives referred to in Croatian linguistics as true adjectives are similar regarding their syntactic structure. The paper analyses the collocation potential of the past participles based on data from the Croatian Collocation Database (http://ihjj.hr/kolokacije/english/) developed at the Institute of Croatian Language and Linguistics. The article describes both the use of the past participles in the multiword units in Croatian and their status in contemporary Croatian dictionaries. What is described are the criteria for distinguishing the past participles as morphological forms of the verb headword from the lexicalised adjectives that should have the status of independent headwords in the dictionary.