Pre-exposure prophylaxis (PrEP) is an evidence-based strategy for HIV prevention, particularly for high-risk populations such as people who inject drugs and engage in chemsex. In Italy, there is no data on the actual knowledge of PrEP among Healthcare professionals (HCPs) in substance use disorder services (SerDs). This study aimed to assess PrEP awareness among SerD HCPs, also exploring their level of knowledge, practice, training, and perceived barriers. A cross-sectional study was conducted using a convenience sample of HCPs from SerDs across Italy (2023-2024). The questionnaire addressed sociodemographic and work-related information, PrEP awareness, knowledge scores (i.e. percentage of correct answers) on when proposing PrEP and reimbursement criteria, practice, and training received. Multiple logistic regression was performed to explore associations with PrEP awareness. The sample consisted of 306 professionals (26.8% physicians). Only 44.8% were aware of PrEP, with lower awareness among non-physicians (p < 0.001). As for knowledge scores on when proposing PrEP and on reimbursement, the median was 57.14% (IQR: 42.86-71.43%) and 55.56% (IQR: 33.33-66.67%), respectively. No differences were reported across professional roles. Only 10.36% reported PrEP is offered at their workplace and 87.9% highlighted a lack of training. Additionally, 96.79% believed it would be appropriate for HCPs to receive PrEP training; however, nurses were the most likely to state it is not appropriate (p = 0.046). The study identified gaps in PrEP knowledge and training among SerD professionals, including physicians. The strong interest in training suggests that SerD HCPs, though with varying perceptions, may be a receptive group for interventions for improving PrEP implementation.© 2025. The Author(s).