This study aimed to investigate the relationship between body condition score (BCS) and serum biochemical parameters in Hanwoo cattle, considering the significant changes in body size that have occurred over the past two decades. A total of 45 clinically healthy Hanwoo cattle were categorized into three BCS groups: group 1 (BCS: 3.0∼3.25), group 2 (BCS: 3.5∼3.75), and group 3 (BCS: 4.0∼ 4.25). Blood samples were collected and analyzed for the total number of 16 biochemical parameters. Significant differences were observed in blood urea nitrogen (BUN), gamma-glutamyl transferase (GGT), triglycerides (TG), and the BUN/creatinine ratio among these groups. Additionally, significant correlations were found between BCS and several parameters, including GGT, glutamic-pyruvic transaminase (GPT), TG, total protein (TP), and globulin (GLOB). The increase in BUN and BUN/ creatinine ratio in high BCS groups was attributed to increased protein intake during the fattening stage rather than renal dysfunction. Furthermore, significant positive correlations between BCS and biochemical parameters including TG, TP, and GLOB might be associated with mild or subclinical hepatic lipidosis, likely due to increased protein intake rather than liver disease. Notably, GPT levels showed a negative correlat...