The present study included (55) colorectal cancer (CRC) patients (men and women) and (35) voluntary healthy subjects. The serum cathepsin B was calculated by ELISA in order to investigate the relationship between this biomarker and gender, age, histopathological type, stages, grades, tumor location, as well as body mass index (BMI). The findings indicated significant increases (p<0.05) in the sera levels of cathepsin B of CRC patients in comparison with the control groups. Cathepsin B levels differed significantly (p<0.05) according to age, histopathological type, stages, and grades, while there were non-significant differences (p<0.05) for gender, tumor location, and BMI. These findings imply that cathepsin B may be implicated in colorectal tumor malignancy at multiple levels, and that the specific activity of this marker could be of relevance as an independent predictive factor for CRC disease progression. Furthermore, our findings support the clinical application of cathepsin B as a routine test in medical laboratories, as this biomarker has a significant prognostic impact in patients with CRC.