Cross-sectional imaging modalities such as ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and Positron emission tomography (PET)/CT have benefited from rapid technical advances in recent years. In patients with colorectal tumors, multislice CT is the standard technique for preoperative evaluation and follow-up. It is faster than single-slice helical CT and allows for excellent 3D imaging of liver anatomy and tumor volumetry. The most accurate technique for detecting and characterizing focal liver lesions is MRI using state-of-the-art scanners and liver-specific contrast agents and should be used for preoperative evaluation of all possible surgical candidates. Whole-body FDG-PET and PET/CT are most useful in the detection of extrahepatic disease and may alter clinical management in up to 20% of patients by detecting extrahepatic spread of disease.