In both Crohn’s disease and Ulcerative Colitis, Colorectal Cancer (CRC) secondary prevention basically relies on the histology detection of dysplasia. In Inflammatory Bowel Diseases (IBD) setting, dysplasia identifies the subgroup of patients eligible to a (more) strict surveillance program (or prophylactic colectomy). In the clinical practice, a number of issues might affect the benefit of the clinico-pathological surveillance of the IBD-dysplasia-patients: sampling errors, inconsistency in biopsy assessment, patients’ drop-out, etc. Even in such a multifaceted context, evidence has been provided that surveillance of dysplasia is effective in reducing both CRC mortality and morbidity. This manuscript focuses on current issues concerning the histology assessment of the IBD-associated dysplastic lesions.