Individuals older than 60 years of age have multiple simultaneous diseases, for which the average number of medications is greater than five, leading up to 3% possibility of having an adverse reaction event. To detect potential drug-drug interactions (PDDIs) and report the average hospital stay for severity potential PPIs, in adults 60 years of age and older in an Internal Medicine Service. This was a retrospective analysis with a review of the clinical records of patients 60 years of age and older. The length of stay, number and type of prescribed daily medications, PDDIs, and number of admission diagnoses for each patient, were reviewed. This study included 342 patients with an average and standard deviation of 6 ± 3.0 medications per day. The PDDI levels were 27 (7.9%) severe, 94 (27.5%) moderate, and 61 (17.8%) had both types of interactions. Severe interactions, presented a hospital stay of 10 days, and moderate interaction a 13-day stay. The most common interactions and their average length of stay may be utilized for quality evaluation of the medication process of such a major patient population as that of the older adult in the hospital setting.