Background Sarcopenia, as diagnosed by the former EWGSOP1 guidelines, was prevalent in cancer patients. The aim of this study was to examine the diagnostic capabilities of the previous and current guidelines, and to compare the clinicopathological features between patients diagnosed using the algorithms comprising the EWGSOP1 and EWGSOP2 guidelines. Methods We conducted a study including colorectal cancer patients from July 2014 to July 2019. The skeletal muscle mass, muscle attenuation, handgrip strength, and 6-meter usual gait speed were prospectively measured to define sarcopenia once patients were hospitalized. Results Of a total of 840 patients, 160 (19.0％) patients were diagnosed with sarcopenia based on the EWGSOP1 and 241 (28.7％) patients were diagnosed based on the EWGSOP2. The numbers of patients diagnosed with sarcopenia and severe sarcopenia were much higher when the EWGSOP2 guidelines were used (160 vs. 241 and 74 vs. 140, respectively). The patients with EWGSOP2-defined sarcopenia showed a lower plasma albumin concentration (37.4 vs. 36.4, P = 0.039) but higher BMI (21.01 vs. 22.22, P < 0.001) than the patient diagnosed based on the EWGSOP1 guidelines. Conclusion The diagnosis of sarcopenia based on screening using the EWGSOP1 and EWGSOP2 guidelines differs considerably, at least in patients with colorectal cancer. In addition, the patients with EWGSOP2-diagnosed sarcopenia also showed a trend toward a lower plasma albumin level and higher BMI.