Aim. Patients with schizophrenia frequently report disturbed sleep and excessive daytime sleepiness. In this study the sleep quality and daytime sleepiness of patients hospitalized due to psychotic disorders was assessed shortly before the discharge from the hospital. Method. 62 patients treated with antipsychotics (20 F/ 42 M, mean age 25.7 +/- 3.5) were examined. The patients performed a vigilance task (Mackworth clock test), clinical scales were used for the assessment of: sleep quality (Athens insomnia scale - AIS), daytime sleepiness (Epworth sleepiness scale - ESS), clinical global impression (CGI scale), drug side effects (UKU scale), psychopathology and depressive symptoms (PANSS and CDSS scales). Results. Excessive daytime sleepiness (EDS) was reported in the UKU scale in 58% of the patients. This subjective sensation of EDS was not reflected in the results of the standardized methods for the assessment of EDS. In the ESS scale EDS was found in 20% of the patients. A disturbed vigilance was found in the vigilance task in 32% of the patients. Conclusion. Subjective feeling of EDS is common in patients treated with antipsychotics. The ESS scale allows to verify the patients' claims. EDS resulting from disturbed or shortened sleep, should be differentiated from sedation resulting from pharmacological treatment and fatigue that may be related to somatic or mental disorders.