Colorectal cancer is a common malignancy often requiring adjuvant chemotherapy. Familial Mediterranean Fever is a chronic hereditary disease which is relatively prevalent in the Middle East and is associated with recurrent episodes of serosal, synovial or cutaneous inflammations. The aim of this paper was to describe a patient with Familial Mediterranean Fever who received fluorouracil-based adjuvant chemotherapy for colorectal cancer. A 56-year-old man with Familial Mediterranean Fever and amyloidosis was referred for evaluation and treatment following surgery for colorectal cancer. In light of his relatively young age, good general state of health and apparently well-controlled Familial Mediterranean Fever, he was treated with chemotherapy consisting of four cycles of 5-fluorouracil and leucovorin. The patient's clinical course during chemotherapy was unremarkable except for one minor attack of Familial Mediterranean Fever. The patient's follow-up was notable for periodic fluctuations in serum carcinoembryonic antigen levels, up to 4-fold of normal. The Familial Mediterranean Fever remained stable. Although our patient showed a good tolerability of treatment, the administration of chemotherapy to patients with Familial Mediterranean Fever raises several concerns. These include a potential deterioration in the Familial Mediterranean Fever status owing to chemotherapy-induced stress, the potential effect of Familial Mediterranean Fever or its treatment on the tolerability of chemotherapy and an overlapping toxicity of the drugs used to treat the two diseases. An increase in serum carcinoembryonic antigen in this setting may be related to the underlying pathophysiologic mechanism of Familial Mediterranean Fever but does not necessarily indicate disease recurrence. Clinicians should be aware of these issues considering the recent worldwide increase in colorectal cancer.