In the tumor microenvironment coexisting with Hashimoto's thyroiditis (HT), cytokines secreted by the tumor cells, stroma cells, or immune cells play a critical role in the regulation of tumor growth, invasion, and metastasis. The present study aims to understand cytokine production from cancerous tissues (CT), para-cancerous tissues (PT), and serum in patients with papillary thyroid carcinoma (PTC) with or without accompanying HT. Using a multiplexed human cytokine assay, we found that nine cytokines, including Interleukin-1alpha (IL-1 alpha), Interleukin-beta (IL-1 beta), Interleukin-12p70 (IL-12p70), Interleukin-8 (IL-8), Interferon-inducible protein-10 (IP-10), Monocyte chemoattractant protein-1 (MCP-1), Macrophage inflammatory protein-1alpha (MIP-1 alpha), Macrophage inflammatory protein-1beta (MIP-1 beta), and soluble E-selectin (sE-Selectin), showed significantly higher expression in paracancerous tissues of HT+PTC compared with HT-PTC (P<0.05). In addition, H&E staining showed immune cell infiltration in PT but not in CT. Moreover para-cancerous tissues of HT+PTC patients produced more Interferon-alpha (IFN-alpha) (P=0.048) and Interferon-gamma (IFN-gamma.) (P=0.004) compared with cancerous tissues, and production of Intercellular cell adhesion molecule-1 (ICAM-1) was significantly higher in CT than PT both in HT+TC (P=0.001) and HT-PTC (P=0.012) patients. To conclude, autoimmune HT was found to affect the cytokine profiles in patients with PTC by stimulating secretion of Th1-type cytokines and chemokines, but further studies are needed to determine the significance of these findings and to reveal