AIM: In patients with colorectal cancer an accurate diagnostic work-up is mandatory in order to perform the most specific treatment. In this study, we aimed to evaluate the accuracy of computed tomography (CT), magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) for detection of regional lymph node metastases (RLNMs) and the additional value of PET/CT in the preoperative staging of colorectal cancer. MATERIAL AND METHODS: From June 2015 to May 2018, 72 colorectal cancer patients were preoperatively examined using CT, MRI, and PET/CT. Histopathological examination of regional lymph nodes were performed in 53 patients who underwent colorectal surgery. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy (ACC) of CT, MRI, and PET/CT for RLNMs, and the additional value of PET/CT in distant metastases were determined. RESULTS: There were 44 male and 28 female in our study. The mean age was 61±11 years. Histopathologically, 27 patients (51%) were negative and 26 patients (49%) were positive for RLNMs. The sensitivity, specificity, PPV, NPV, and ACC of PET/CT were 88.5%, 59.3%, 67.6%, 84.2%, and 73.6%, respectively. PET/CT changed the patient management with diagnostic contribution to the suspicious lesions identified by radiological imaging modalities. CONCLUSION: PET/CT is a useful tool in the evaluation of colorectal cancer, and it allows to metabolically characterize undetermined lesions suspected for recurrence of disease, to perform a complete pre-surgical staging and to identify occult metastatic disease. PET/CT should be considered an essential diagnostic tool in the management of patients with colorectal cancer, especially in the preoperative staging.