This study examines the differences among the importance and frequency of librarians' duties in public libraries of different sizes in Greece, and it considers whether they have been influenced by the economic crisis. In this respect, 43 public libraries' managers evaluated 116 duties. To identify the significant differences among the libraries with respect to both their number of users and material sizes, a two-way analysis of variance was conducted. The results showed, regarding duties' importance, significant differences for the subcategory of user education according to libraries' number of users. Number of users was also related to the frequency of the subcategory collection development planning. Materialsize was significantly associated with the frequency of material ordination, and software management duties. Findings can be helpful for appropriate strategic planning, and for supporting specific actions to advance libraries' intellectual contribution.