This prospective observational study was designed to clarify the rate of peripheral intravenous catheter, especially short peripheral catheter, failures among adult patients in medical and surgical wards. The study was conducted during a 2-month period at a university hospital in Tokyo, Japan. A total of 5316 catheters from 2442 patients were studied. The rate of catheter removal as a result of catheter failure was 18.8%. The reasons for removal in catheter failures were infiltration (41.3%) and pain (19.3%). Pain was a major reason for catheter failure and removal. For this reason, observing changes under the skin before signs and symptoms appear might help prevent catheter failures.