Aim is the development of a work-related support intervention, tailored to the severity of work-related problems of patients diagnosed with gastrointestinal (GI) cancer treated with curative intent. Two methods were used: (1) Work-related problems were identified from the literature and submitted to an expert panel during a modified Delphi study. Experts allocated work-related problems into degrees of severity: mild, severe or complex. In addition, experts indicated which health care professional should provide the tailored support: (2) These outcomes were combined with existing interventions to design the tailored intervention. Semi-structured interviews with experts were conducted to assess whether the intervention was comprehensive, and feasible for daily practice. A decision diagram measuring severity of work-related problems was developed based on the modified Delphi study with 44 experts, encompassing social, disease and occupational problems. Based on the degree of severity, support was provided by: an oncological nurse (mild), oncological occupational physician (severe) or multidisciplinary team (complex). The intervention encompassed three individual meetings in the clinical setting and was considered comprehensive and feasible by 12 experts. The intervention is innovative in combining oncological and occupational care in the clinic and being tailored to the needs of GI cancer patients with specific work-related problems.