Seniors are much more sensitive to adverse drug events and therefore safe pharmacotherapy is one of the main priority in the aging population. Diuretic agents are medications that are often prescribed in older population and may pose a significant risk of adverse drug events, e.g. dehydration, orthostatic hypotensions, falls, ion dysbalances and other serious side effects. The aim of this diploma thesis was to investigate inappropriate prescribing of diuretics in Czech ambulatory care seniors participating in the EUROAGEISM H2020 project, FIP7, and to discuss potential links of such inappropriate prescribing to aspects of ageism.