Sarcopenia and inflammation are independently associated with worse survival in cancer patients. This study aims to determine the impact of sarcopenia, body mass index (BMI), and inflammatory biomarkers on survival in advanced hepatocellular carcinoma (HCC) patients treated with anti-PD-1 antibody-based immunotherapy. A retrospective review of advanced HCC patients treated with immunotherapy at Winship Cancer Institute between 2015 and 2019 was performed. Baseline computed tomography and magnetic resonance images were collected at mid-L3 level, assessed for skeletal muscle density using SliceOmatic (TomoVision, version 5.0) and converted to skeletal muscle index (SMI) by dividing it by height (m2). Sex-specific sarcopenia was defined by the median value of SMI. The optimal cut for continuous inflammation biomarker was determined by bias-adjusted log-rank test. Overall survival (OS) was set as primary outcome and Cox proportional hazard model was used for association with survival. A total of 57 patients were included; 77.2% male, 52.6% Caucasian, 58.5% Eastern Cooperative Oncology Group performance status 0-1, 80.7% Child Pugh A. Treatment was second line and beyond in 71.9% of patients. The median follow-up time was 6 months. Sarcopenia cut-off for males and females was SMI of 43 and 39, respectively. 49.1% of patients had sarcopenia. Median OS was 5 versus 14.3 months in sarcopenic versus nonsarcopenic patients (Log-rank P=0.054). Median OS was 5 and 17.5 months in patients with BMI <25 and BMI ≥25, respectively (Log-rank P=0.034). Median OS was 3.6 and 14.3 months for patients with neutrophil-to-lymphocyte ratio (NLR) ≥5.15 versus NLR <5.15 (Log-rank P<0.001). In multivariable Cox regression model, higher baseline NLR was associated with worse OS (hazard ratio [HR]: 4.17, 95% confidence interval [CI]: 1.52-11.39, P=0.005). Sex-specific sarcopenia showed a trend of worse OS (HR: 1.71, 95% CI: 0.73-4.00, P=0.215) but was not statistically significant. BMI<25 was associated with worse OS (HR: 2.28, 95% CI: 0.92-5.65, P=0.076). In the association with progression free survival, neither baseline BMI nor sex-specific sarcopenia showed statistical significance. After controlling for baseline Child Pugh score and NLR, sex-specific sarcopenia does not predict OS. Baseline BMI and NLR together may predict OS in advanced HCC patients treated with anti-PD-1 antibody.