A retrospective pharmacoepidemiological study (included data from medical records of 401 patients ≥65 years of age who received treatment in hospitals) was aimed to measure prevalence of potentially prescribing omissions (PPOs) among older people using Screening Tool to Alert doctors to Right Treatment 2 (START-2) criteria (2015) and to investigate associated risk factors. Statistical analysis includes methods of parametric and nonparametric statistics. We compared patients who had PPOs with those had not PPOs. It was found that hypertension, diabetes mellitus and high levels of concomitant diseases were more characteristic for people with PPOs, and they received more medications. There were no significantly differences in terms of age and gender. Polypharmacy was observed in 36,7% of patients. Using the START-2 criteria, 633 episodes of PPOs were indicated (67,3% of patients). 94,7% PPOs were mainly associated with under-use of statins, aspirin, b-blockers and angiotensin-converting enzyme inhibitors. Multivariate analyses revealed strong association of PPOs prevalence with the number of prescribed medications and comorbidities, especially, ischaemic heart disease and hypertension. Cardiovascular medications were the most common among PPOs.