Objective: To investigate the peripheral blood level of carcinoembryonic antigen-related cell adhesion molecular 1 (CEACAM1) in patients with thyroid cancer and its diagnostic value for thyroid cancer. Methods: Using ELISA assay, the serum CEACAM1 levels in 76 thyroid cancer patients, 48 patient with benign thyroid tumor and 38 healthy subjects were determined, and meanwhile, the levels of carcinoembryonic antigen (CEA) and thyroglobulin (TG) were also measured. The relations of CEACAM1 level with clinicopathologic characteristics of thyroid cancer were analyzed. Through drawing ROC curves, the diagnostic values for thyroid cancer among CEACAM1, CEA and TG were compared. Results: The serum CEACAM1 level in thyroid cancer patients was significantly higher than that in patients with benign thyroid tumor or healthy control individuals (547.11 ng/mL vs. 469.77 ng/mL and 369.04 ng/mL, both P<0.05). The serum CEACAM1 level was significantly associated with TNM stage and lymph node metastasis of thyroid cancer patients (both P<0.05). The area under the ROC curve of CEACAM1 for diagnosis of thyroid cancer was 0.94, with sensitivity of 97.4% and specificity of 80.3%, and the diagnostic value of CEACAM1 for thyroid cancer was superior to that of CEA or TG. Conclusion: Serum CEACAM1 detection has certain value for diagnosis and disease assessment of thyroid cancer.