Serological biomarkers have been rapidly progressing as non-invasive tests for the early detection of inflammatory bowel disease (IBD). Procalcitonin (PCT) is a novel acute-phase reactant protein that is elevated in the inflammatory process, especially in bacterial infections. This study aimed to review the diagnostic value of PCT in IBD activity. However, there were controversies about the role of PCT in the detecting of IBD disease activity. Studies showed varied diagnostic cut-points (ranging from 0.13 to 1.0 ng/dl) and sensitivity up to 93 %. Although the clear role of PCT as a valuable diagnostic marker was not identified in determining disease activity, PCT measurement in addition to other inflammatory markers can improve the diagnostic value of these markers. Moreover, further studies are required to confirm PCT's value in distinguishing IBD disease activity.