in hospitalised patients indicate that sleep is affected during hospitalisation (confirmed change in both quality and quantity), which cannot be related to patient recovery. Materials and Methods: A multicenter cross-sectional study was conducted in hospitalised 340 patients in the standard departments of 7 hospitals in the Czech Republic. Data were collected using two instruments: Ford Insomnia Response to Stress Test (FIRST) and Richards- Campbell Sleep Questionnaire (RCSQ) in the period September 2022 - January 2023. The statistical software SIMCA-P v.12.0 from Umetrics AB (Umeå, Sweden) was used for OPLS analysis. The estimation of the internal consistence was completed using Cronbach's a statistic following Spearman’s correlations. Results: The patients were found to have the worst sleep indicators on the first night hospitalisation, while the quality of sleep improved with the length of stay. Men slept better than women, the effect of age was proven (older people had better quality sleep than younger people), the higher the VAS values in the patients, the worse the quality of their sleep. At the same time, the relationship between the benzodiazepines used and the quality of their sleep was demonstrated in patients. In our study, the FIRST questionnaire did not prove to be a suitable tool to detect vulnerable individuals with sleep disorders. Conclusions: The association between sleep quality and selected variables was statistically proven. It is necessary to look for other tools that would help identify people with sleep disorders.