Adverse medical events place a burden on patients and cause readmissions, which account for about half of all healthcare expenses. This study assessed adverse events as they relate to readmissions in the Military Health System MHS. Among 142,579 admissions with an adverse event in the MHS between January 1, 2007 and December 31, 2014, those with adverse events related to procedures n58,934 and drugs n53,950 were the most prevalent. There was little year to year variation in the rate of adverse event-related admissions by type with the exception of procedure-related adverse events, which decreased noticeably over the nine years of study. While the percentage of readmission was higher after radiation-related adverse events, the majority of the burden of readmission stems from the two most common adverse event types drugs and procedures. In order to reduce the total number of readmissions, special attention should be directed toward patients who are prone to experiencing drug- or procedure-related adverse events.