BACKGROUND: Medication errors and renal impairment contribute to severe adverse drug events, which may lead to hospital admission. OBJECTIVE: To determine whether medication errors and renal impairment contribute to hospital admission and examine these errors for strategies to prevent admissions. METHODS: The 714 medication-related hospital admissions reported in the prospective multicenter study HARM (Hospital Admissions Related to Medication) were analyzed. The patients were divided into 3 groups based on the availability of creatinine levels: group A, the home-monitored group (n = 227); group B, the hospital-monitored group (n = 420); and group C, the unmonitored group (n = 67). RESULTS: After assessment, 70 admissions (10%) were considered to be related to a medication error and renal impairment (A, 29; B, 41; C, none). In these 70 patients, 85 errors occurred in group A, 66 errors in group B, and none in group C. Dosing errors were identified in 46 patients (A, 14; B, 32), a drug-drug interaction in 22 patients (A, 13; B, 9), and a drug-disease interaction in 17 patients (A, 10; B, 7). CONCLUSIONS: Renal impairment and medication errors may lead to medication-related hospital admissions. Monitoring renal function and adjusting pharmacotherapy according to renal function might help to prevent hospital admissions. This can be a strategy for research on how to decrease the number of medication-related hospital admissions.