The use of intravascular or intraluminal catheters is common in geriatric medicine. Blood stream infections due to intravascular catheterization, peritoneal catheters for dialysis, suprapubic or transurethral catheters, or percutaneous endoscopic gastrostomy are a major source of nosocomial infections. Therefore, the prevention of catheter-associated infections is an important issue for physicians and nursing staff working in hospitals or in outpatient settings. The risk can be minimized by diligent checking of the indications, hygienic measures, using the correct materials, thorough follow-up, and education of the medical and nursing staff. Thus, it is possible to avoid individual suffering of patients and to reduce costs in the healthcare system.