Poor sleep is common among patients with medical disorders. Sleep disturbances can be a cause of fatigue and poor quality of life for patients suffering from sarcoidosis. Studies on subjective sleep quality or prevalence of insomnia have not been reported so far.The aim of this study was to investigate the subjectively reported sleep quality and its relation to psychological and physical factors in sarcoidosis patients.1197 patients from Germany diagnosed with sarcoidosis were examined using the Pittsburgh Sleep Quality Index (PSQI), the Medical Research Council (MRC) dyspnea scale, the Hospital Anxiety and Depression Scale (HADS) and the Multidimensional Fatigue Inventory (MFI).802 patients (67%) had PSQI global scores >5, indicating subjectively poor quality of sleep. The mean PSQI score was 7.79 ± 4.00. Women reported a significantly inferior individual quality of sleep than men. The subjective quality of sleep was lowered significantly with increasing dyspnea for men and women. 294 patients (25%) had PSQI global scores >10 usually found in patients with clinically relevant insomnia. In this group 86% had high values for fatigue, 69% for anxiety, and 59% for depression. The prevalence of known sleep apnea was 8.7% and 15.7% for restless legs.Poor subjective sleep quality in sarcoidosis patients is about twice as common as in the general population and is associated with fatigue, anxiety, depression and dyspnea. Questions about sleep complaints should therefore be included in the management of sarcoidosis.