Good manufacturing practice (GMP) inspection at medicines manufacturing sites is a complex procedure which includes meticulous planning. Within the inspection an overview of all processes must be performed, especially ones that are considered to be critical for the product quality and consequently for the patient. Cleaning of premises and equipment is considered to be a critical process hence it should be well defined and validated. Cleaning validation is a documented procedure that proves that removal of the of the traces of active substances and excipients, detergents or any other defined impurities is conducted successfully up to the set limit. Validation protocol has to document the validity cleaning procedures checks and later documented in the report. Any changes in the validated cleaning procedure should risk assessed and the result could be a re-validation. In this thesis two different approaches found in the practice were explained and assessed using a real life examples. Approach specific for the single sterile medicine production was assessed based on example of manufacturing of the sterile product containing active pharmaceutical ingredient busulfan. MACO limit for busulfan is calculated and compared with the values given by manufacturer in validation protocol. Equipment-specific approach was assessed based on another example of the production of six sterile medicine products on the same production line, and for cleaning validation the sterile product containing the active pharmaceutical ingredient desmopresin was selected as the most critical based on the ADE value. The risk assessment determined that cleaning validation does not support production of eptifibatide injection after production of desmopresin injection. Cleaning validation supports the production of other injections in the production line after the production of desmopressin injection.