The global prevalence of obesity continues to rise. However, whether obesity affects the degree of intra-abdominal solid organ damage following blunt trauma remains unclear. This study aimed to investigate the correlation between obesity and intra-abdominal solid organ damage. This cross-sectional study was conducted at a regional trauma center in the Republic of Korea from January 2018 to December 2022 and included 582 patients aged 18-98 years with blunt abdominal trauma. Patients were categorized into four groups-underweight, normal weight, overweight, and obesity-based on their body mass index (BMI). Odds ratios (ORs), beta coefficients, and 95% confidence intervals (CIs) for intra-abdominal organ damage were calculated across BMI categories using multiple logistic regression analysis after adjusting for the confounding variables. The obesity group exhibited a significant decrease in the prevalence of liver injury (OR: 0.553, CI: 0.316 to 0.966) and a reduction in liver injury severity (β: -0.214, CI: -0.391 to -0.037) compared with the normal-weight group after adjusting for the confounding factors. However, no significant association was observed between the BMI and injuries to other solid organs, such as the spleen, pancreas, and kidneys. Additionally, the younger obesity group (participants aged < 45 years) exhibited a significant negative association with both liver injury and injury grade. However, the older obesity group (participants aged > 65 years) exhibited a statistically significant association only with the liver injury grade compared with the normal-weight group. Obesity can serve as a predictive factor for the presence and severity of liver damage caused by blunt abdominal trauma.