Objective: The goal of this prospective observational study was to identify adverse events (AEs) related to the use of intravenous access sites used for infective endocarditis (IE) treatment in a tertiary care hospital. Design: This is an observational, analytical and prospective study on AEs resulting from the use of intravenous access sites in patients under antimicrobial treatment for IE. Patients enrolled in the International Collaboration on Endocarditis (ICE) study had their peripheral, short-term central catheters (CVC) and peripherally inserted central catheters (PICC) monitored for AEs. Setting: Tertiary care hospital for cardiac surgery in Rio de Janeiro, Brazil. Patients: Patients over 14 years of age, hospitalised in 2009 and 2010 with possible or definite criteria for IE by the modified Duke criteria were included. Main outcome measures: AEs related to intravenous catheters: erythema and infiltration, fever, obstruction, externalisation and blood stream infection. Results: Thirty-seven episodes of IE in 35 patients were studied. Mean patient age was 44.32±15.2 years; 22 (63%) were men. The number of vascular catheters studied were 253, 148 of which were peripheral, 85 CVC (21 of which for haemodialysis) and 20 PICC. The most frequent AEs were ‘erythema’ and ‘infiltration’ for peripheral catheters, ‘fever’ for CVCs and ‘obstruction’ and ‘externalisation’ for PICCs. The number of catheterdays was 360 for peripheral catheters, 1.156 for CVC and 420 for PICC. Kaplan-Meier curves for CVC and PICC showed statistical difference for obstruction (p<0.001) in PICCs. More bacteraemia occurred in CVC compared with PICC. Conclusions: The choice of intravenous access sites is critical in the treatment of IE. Close observation for AEs and stricter implementation of infection control measures and better manipulation of catheters are suggested.