BACKGROUND: In recent years, an increasing number of patient-reported outcome assessment tools (PROs) have been developed specifically to ascertain patients' perceptions of different drug treatments. Among them, the injection process has been analysed, especially in patients chronically treated with chronic biological therapies. One of the main advantages of most current biological therapies is the possibility to self-administer medication at home through the use of a variety of devices, including prefilled syringes (PFS) and prefilled pens (PFP). OBJECTIVES: The aim of this study was to conduct qualitative research to assess the degree of preference between the different pharmaceutical forms PFS and PFP. METHODS: We performed a cross-sectional observational study in patients on biological drug therapy through the compilation of a web-based questionnaire at the time of routine delivery of biological therapy. Questions regarding primary diagnosis, adherence to therapy, the preferred pharmaceutical form and the main reason for preference among five possibilities already reported in the scientific literature were included. RESULTS: During the study period, data were collected from 111 patients and 68 (58%) indicated PFP as their preference. From the analysis of reasons that led a patient to choose one device over another, PFSs are chosen mainly out of habit (n=13 (28.3%) PFS vs n=2 (3.1%) PFP) while PFPs are chosen to avoid needle vision (n=15 (23.1%) PFP vs n=1 (2.2%) PFS). Both differences were found to be statistically significant (p<0.001). CONCLUSION: As biological subcutaneous drugs are increasingly prescribed for a wide variety of long-term therapies, further research focused on identifying patient factors which may enhance adherence to treatment will become even more valuable.