Abstract: This study is driven by the increasing prevalence of colorectal cancer and the need for rapid, non-invasive, and accurate diagnostic methods. Carbohydrate antigen 242 (CA242) and carcinoembryonic antigen (CEA) is a tumor marker with the potential to serve as a diagnostic predictor for colorectal cancer. An analytical observational study with a cross-sectional design was conducted. The study included 58 subjects, comprising 29 colorectal cancer patients and 29 control subjects. Both groups underwent CEA and CA242 testing using the ELISA method at RS Adam Malik.