The diagnosis and monitoring of Crohn's disease has traditionally relied on clinical assessment, serum markers of inflammation, and endoscopic examination. Fecal biomarkers such as calprotectin, lactoferrin, and S100A12 are predominantly derived from neutrophils, are easily detectable in the feces, and are emerging as valuable markers of intestinal inflammation. This review focuses on the role of fecal biomarkers in the diagnosis and monitoring of Crohn's disease, in particular how these biomarkers change with disease activity and remission, how they can be used to monitor the response to medical therapy, their value in predicting clinical relapse, and their role in monitoring the postoperative state.