Despite enormous clinical experience of using peripheral vascular catheters, there is still controversy over the incidence and clinical relevance of bloodstream infections caused by these devices and the measures for preventing them. We performed a prospective study to determine the clinical epidemiology and outcomes of nosocomial bloodstream infections caused by short- and mid-line peripheral venous catheters among a group of non-intensive care unit patients. Cases of peripheral venous catheter-related bloodstream infections (PVC-BSIs) were compared to cases of central venous catheter-related bloodstream infections (CVC-BSIs). From October 2001 to March 2003, 150 cases of vascular catheter-related bloodstream infections were identified among 147 patients. Seventy-seven episodes (0.19 cases/1000 patient-days) were PVC-BSIs and 73 episodes (0.18 cases/1000 patient-days) were CVC-BSIs. Compared with CVC-BSIs, patients with PVC-BSIs more often had the catheter inserted in the emergency department (0 vs 42%), had a shorter duration from catheter insertion to bacteraemia (mean: 15.4 vs 4.9 days) and had Staphylococcus aureus (33 vs 53%) more frequently as the causative pathogen. Among patients with PVC-BSIs, catheters inserted in the emergency department had a significantly shorter duration in situ compared with those inserted on hospital wards (mean: 3.7 vs 5.7 days). Patients with PVC-BSIs caused by S. aureus had a higher rate of complicated bacteraemia (7%) and higher overall mortality (27%) than patients with PVC-BSIs caused by other pathogens (0 and 11%, respectively). Bloodstream infections remain underestimated and potentially serious complications of peripheral vascular catheterisation. Targeted interventions should be introduced to minimise this complication.