Background: Liver cancer is the sixth most common cancer and the third leading cause of cancer mortality worldwide. There are two main types of primary liver cancers; hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma. HCC accounts for around 80% of primary liver cancer cases. Generally, HCC develops in genetically susceptible individuals with risk factors, especially in the presence of cirrhosis. Cirrhosis is a systemic disease, and malnutrition is a key feature as well as an important complication which can be associated with worse outcomes. In this study, we aim to characterize the potential effects of malnutrition on HCC patients with underlying cirrhosis. Methods: The United States Nationwide Inpatient Sample (NIS) was used to extract hospitalization data of patients admitted between 2016 to 2018. Using ICD10 revision codes, we identified adults with the diagnosis of cirrhosis who have HCC with concomitant malnutrition, including sarcopenia. The control group included cirrhotic HCC patients without malnutrition. The primary outcome was the in-hospital mortality. Secondary outcomes included encephalopathy, ascites, variceal bleed, hepatorenal syndrome (HRS) and length of stay (LOS). Multivariate logistic regression was used to adjust for relevant variables. Results: We identified 423,158 patients admitted with cirrhosis. 20,582 had HCC, and of those, 2560 patients had the diagnosis of malnutrition. In this group of patients, the mean age was 59.85 years. 30% were females and 62% were Caucasians. When adjusted to other relevant variables, malnutrition was associated with increased in-hospital mortality (OR 1.40; P-value 0.000). It was also associated with an increased chance of developing encephalopathy (OR 1.42; P-value 0.000), ascites (OR 1.62; P-value 0.000), and HRS (OR 1.33; P-value 0.000). Moreover, it was associated with increased LOS (OR 1.99; P-value 0.001). Other factors associated with increased in-hospital mortality in cirrhotic HCC patients are described in the table. Conclusions: Malnutrition is a common complication in patients with cirrhosis. If identified, it can be treated efficiently. In this study, cirrhotic HCC patients with malnutrition had an increased chance of mortality. Further, they were at increased risk for cirrhosis decompensation and other in-hospital complications, which in turn can lead to increased LOS and therefore increased financial burden. We recommend that clinicians pay attention to patients with malnutrition and to treat them in order to prevent these complications.