Background: Globally, 697.5 million people—9.1% of the world’s population—suffer from chronic kidney disease (CKD). In Mongolia, diseases of the kidney and urinary tract rank third in overall morbidity and are a leading cause of hospital admissions. Due to the asymptomatic and progressive nature of these diseases, early diagnosis of CKD has become a critical issue in recent years. One such early diagnostic marker is KIM-1 (Kidney Injury Molecule-1). KIM-1 is synthesized in the epithelial cells of the proximal tubule during renal injury and serves as a receptor for the phagocytosis of apoptotic cell debris. It is considered a promising biomarker for the early detection of kidney damage. Aim: To evaluate the relationship between KIM-1 (Kidney Injury Molecule-1) and clinical biochemical parameters in patients with chronic kidney disease. Materials and Methods: An analytical case-control study was conducted. A total of 54 participants were involved: a case group of 26 and a control group of 28. The case group included 26 patients with chronic kidney disease who were being treated at the Emergency and Internal Medicine departments of the First Central Hospital of Mongolia (FCHM). Serum KIM-1 protein levels were determined using an Enzyme-Linked Immunosorbent Assay (Human Kim-1 ELISA Kit, Cat: ELK2287). Statistical analysis was performed using SPSS-23.0, while text processing and data visualization were conducted using Microsoft Office. Result: KIM1 levels are positively correlated with creatinine, urea, uric acid, glucose, and potassium, and inversely correlated with calcium, total protein, and albumin, indicating a correlation with clinical biochemical parameters. The mean level of KIM-1 protein was 1379±208.3 pg/mL in the chronic kidney disease group and 91.19±22.09 pg/mL in the control group, showing a statistically significant difference between the two groups (p<0.0001). ROC analysis for KIM-1 (pg/mL) showed an Area Under the Curve (AUC) of 0.979 (95% CI: 0.951–1.000, p<0.001). The optimal diagnostic cut-off value was determined at KIM-1 236.17 pg/mL, where sensitivity reached 96.2% and specificity 92.9%, with the highest Youden index (0.89). Conclusion KIM1 levels were positively correlated with creatinine, urea, uric acid, glucose, and potassium, and inversely correlated with calcium, total protein, and albumin. KIM1 protein levels were significantly higher in patients with chronic kidney disease, suggesting that KIM1 is a highly sensitive and specific biomarker for the diagnosis of CKD.