Balanced and safe prescribing is difficult to achieve in frail older adults with multiple comorbid diseases. This issue is of particular concern, especially in elderly hospitalized patients because hospitalization exposes such individuals to an increased risk of adverse drug reactions (ADRs). The avoidance of medications that are considered to be inappropriate is among the interventions for treatment options in elderly patients. A potentially inappropriate medication (PIM) is a drug in which the risk of an adverse event outweighs its clinical benefit, particularly when there is a safer or more effective alternative therapy for the same condition. Explicit criteria have been developed to identify PIMs and among these, Beers' criteria are the most frequently applied in the literature. However, evidence suggests that such criteria cannot easily be applied to elderly hospitalized people in European countries; approximately 20% of drugs listed in Beers' criteria are rarely prescribed or are not available in Europe, and Beers' listed PIMs are not associated with inhospital mortality, length of hospital stay and/or ADRs in Italian studies. On the contrary, ADRs can contribute to accelerated functional decline in elderly hospitalized patients independently of the use of Beers' listed PIMs. Therefore, we will review the evidence pertaining to the application of Beers' criteria in elderly hospitalized patients, while focusing on Italian studies that have investigated the role of PIMs as potential predictors of negative hospital outcomes. In addition, we will also review the available evidence regarding new European criteria on identifying PIMs, because clinical application in elderly hospitalized Europeans is still under investigation.