Background: Higher prevalence of multiple illnesses and cognitive impairment among older patients pose a risk of comprehension difficulties, potentially leading to medication errors. Therefore, the objective of this study was to investigate comprehension of discharge -instructions among older patients admitted to a Quick Diagnostic Unit (QDU). Methods: One hundred and two patients discharged from the QDU answered a questionnaire covering understanding of their hospitalization and discharge plan. Patients' ability to recall discharge instructions and awareness of comprehension deficits, ie, ability to identify the misconceived information, were evaluated by comparing the questionnaires with the discharge letters. The population was divided into an older group (age ≥65 years) and a younger group. Results: The older group (n=40) was less able to recall correct medication instructions when compared to the younger group (54% versus 78%, respectively; P=0.02). In multiple logistic regression analysis, correct recall of medication instructions was 4.2 times higher for the younger group compared to the older group (odds ratio 4.2, 95% confidence interval 1.5-11.9, P=0.007) when adjusted for sex and education. The older patients were less aware of their own comprehension deficits, and in respect to medication instructions awareness decreased 6.1% for each additional year of age (odds ratio 0.939, 95% confidence interval 0.904-0.98, P=0.001) when adjusted for sex and education. Conclusion: Older patients were less able to recall correct medication instructions and less aware of their comprehension deficits after discharge from a QDU. The findings of the present study emphasize the importance of thorough communication and follow-up when treating older patients.