Objectives Despite widespread use of medical devices and their increasing complexity, their contribution to unintended injury caused by healthcare (adverse events, AEs) remains relatively understudied. The aim of this study was to gain insight in the incidence and types of AEs involving medical devices (AMDEs). Methods Data from two patient record studies for the identification of AEs were used. Identification of AMDEs was part of these studies. Patient records of 6894 admissions of a random sample of 20 hospitals in 2011/2012 and 19 hospitals in 2015/2016 were reviewed for AMDEs by trained nurses and physicians. Results In 98.7% of the admissions, a medical device was used. Adverse events involving medical devices were present in 2.8% of the admissions, with 24% of the AMDEs being potentially preventable. Of all AEs, in 40%, medical devices were involved. Of all potentially preventable AEs, in 44%, medical devices were involved. Implants were most often involved in potentially preventable AMDEs. Conclusions Medical devices are substantially involved in potentially preventable AEs in hospitals. Research into AMDEs is of great importance because of the increasing use and complexity of medical devices. Based on patient records, most improvements could be made for placement of implants and prevention of infections related to medical devices. Safety and safe use of medical devices should be a subject of attention and further research.