Fatigue is a highly prevalent and debilitating symptom in cancer survivors. The aim of this study was to assess the impact of fatigue and other cancer-related symptoms on the return to work of cancer survivors. A prospective inception cohort study with 12 months of follow-up was initiated. At 6 months following the first day of sick leave, levels of fatigue, depression, sleep problems, physical complaints, cognitive dysfunction and psychological distress were assessed, in addition to clinical, sociodemographic and work-related factors. Data were obtained from one academic hospital and two general hospitals in the Netherlands. 235 patients who had a primary diagnosis of cancer and underwent treatment with curative intent were included. The rate of return to work was measured at 6, 12 and 18 months. Hazard ratios (HRs) for the duration of sick leave up to 18 months following the first day of sick leave were calculated. The rate of return to work increased from 24% at 6 months to 64% at 18 months following the first day of sick leave. Fatigue, diagnosis, treatment type, age, gender, depression, physical complaints and workload were all related to the time taken to return to work. Fatigue scores were also strongly related to diagnosis, physical complaints, and depression scores. Fatigue at 6 months predicted a longer sick leave with a hazard ratio of 0.71 (95% Confidence Interval (C.I.) 0.59-0.85), adjusted for diagnosis, treatment type, age and gender. In a multivariate Cox regression analysis, diagnosis, treatment, age, physical complaints and workload remained the only significant predictors of duration of the sick leave. 64% of cancer survivors returned to work within 18 months. Fatigue levels predicted the return to work. This was independent of the diagnosis and treatment, but not of other cancer-related symptoms. Better management of cancer-related symptoms is therefore needed to facilitate the return to work of cancer patients.