To determine the prevalence, determinants, and potential clinical relevance of adherence with the Dutch dosing guideline in patients with impaired renal function at hospital discharge. Retrospective cohort study between January 2007 and July 2011. Academic teaching hospital in the Netherlands. Patients with an estimated glomerular filtration rate (eGFR) between 10-50 ml/min/1.73 m(2) at discharge and prescribed one or more medicines of which the dose is renal function dependent. The prevalence of adherence with the Dutch renal dosing guideline was investigated, and the influence of possible determinants, such as reporting the eGFR and severity of renal impairment (severe: eGFR<30 and moderate: eGFR 30-50 ml/min/1.73 m(2)). Furthermore, the potential clinical relevance of non-adherence was assessed. 1327 patients were included, mean age 67 years, mean eGFR 38 ml/min/1.73 m(2). Adherence with the guideline was present in 53.9% (n=715) of patients. Reporting the eGFR, which was incorporated since April 2009, resulted in more adherence with the guideline: 50.7% vs. 57.0%, RR 1.12 (95% CI 1.02-1.25). Adherence was less in patients with severe renal impairment (46.0%), compared to patients with moderate renal impairment (58.1%, RR 0.79; 95% CI 0.70-0.89). 71.4% of the cases of non-adherence had the potential to cause moderate to severe harm. Required dosage adjustments in case of impaired renal function are often not performed at hospital discharge, which may cause harm to the majority of patients. Reporting the eGFR can be a small and simple first step to improve adherence with dosing guidelines.