Objectives. The aim of this study was to investigate the role of several cytokines including IL-2, IL-6, IL-8, IL-10, and TNF-alpha in the diagnosis of HPB cancers. Materials and Methods. The prospective studywas performed between October 2007 and September 2014. The study included 226 patients who were divided into 5 groups depending on their postoperative and histopathologic diagnosis: Control group included 30 healthy volunteers. Hepatocellular cancer (HCC) group included 24 patients diagnosed with HCC. Gallbladder cancer (GBC) group included 36 patients diagnosed with GBC. Cholangiocellular carcinoma group included 64 patients diagnosed with cholangiocellular carcinoma. Pancreatic cancer group included 72 patients diagnosed with pancreatic cancer. Serum levels of IL-2, IL-6, IL-8, IL-10, and TNF-alpha were measured using an enzyme-linked immunosorbent assay kit in accordance with the guidelines of the producer. Results. Serum TNF-alpha concentration was significantly higher in the cholangiocellular carcinoma and pancreatic cancer groups compared to other groups. IL- 6 and IL- 10 were significantly increased in both the HCC and GBC groups, IL- 2, IL- 6, IL- 10, and TNF-alpha in the cholangiocellular carcinoma group, and IL- 2, IL- 6, IL- 8, and TNF-alpha in the pancreatic cancer group. Conclusion. We suggest that cytokines can be used as useful markers in the diagnosis of HPB cancers.