The aim of this study was to determine the prevalence and influencing factors of fatigue in cancer survivors. 646 cancer survivors completed the Multidimensional Fatigue Inventory (MFI-20), in addition to the Hospital Anxiety and Depression Scale (HADS), the Quality Of Life questionnaire EORTC QLQ-C30 (European Organization for Research and Treatment of Cancer QLQ-C30), the subscale 'social support' of the Functional Assessment of Cancer Therapy Scale (FACT), the Perceived Adjustment to Chronic Illness Scale (PACIS), and a questionnaire containing items on demographic and clinical data. 36% of cancer survivors suffer from moderate, 12% from severe fatigue. Fatigue was significantly associated with depression, anxiety, sleep difficulties, adjustment to the illness, pain, dyspnoea, age, lacking social support, and sex. Other socio-demographic, cancer-related, and treatment-related factors had no influence on fatigue. Fatigue in cancer survivors is strongly linked to physical and psychological aspects.