Stage is the strongest predictor of survival for patients with colorectal cancer. Accurate staging also is critical for appropriate patient management and meaningful clinical research. Uniform staging criteria applied in a uniform manner are essential for accurate evaluation of therapies and outcomes. Historically, numerous different staging systems for colorectal cancer have been employed, but a single internationally recognized system is required to ensure a common language for cancer that is understood by clinicians in all specialties. For the tumor, node, metastasis system to remain relevant, it has to continuously undergo critical evaluation and change when clinically indicated.