Objectives: In this study, we aimed to investigate the prognostic impact of serum LDH for survival and AKI outcomes compared with serum creatinine phosphokinase (CPK) levels among adult hospitalized patients with COVID-19 infection Methods: We enrolled a total of 1,183 adult hospitalized patients with COVID-19 infection in an infectious disease specialized hospital of Republic of Korea from December 2020 to September 2021. Serum LDH and CPK levels were selected as provisional prognostic factors. Outcome variables included all cause in-hospital mortality and AKI during admission. Hazard for mortality was analyzed using multivariable Cox including age, sex, body mass index, hypertension, and diabetes mellitus. Risk for AKI was analyzed using multivariable logistic regression Results: Patients’ mean age was 56.5 ± 20 years old, and mean estimated glomerular filtration rate was 82.0 ± 38.1 ml/min/1.73m(2). Initial LDH levels were 440.9 ± 202.3 (unit/L), CPK levels 170.7 ± 606.5 (unit/L). A total of 143 (12.1%) mortality and 322 (27.2%) AKI events occurred during a median 14 days of admission period. Serum initial LDH levels categorized as quartile were significantly associated with increased mortality in Kaplan-Meier analysis (P < 0.001). However, initial CPK levels were not (P = 0.076). In multivariable Cox analysis, high serum initial LDH levels were associate with mortality (HR 2.81, 95%CI 1.45-5.45, P = 0.002, overall P < 0.001). Patients with higher initial LDH levels showed longer duration of hospitalization (LDH Q4 vs. Q1: 19.0 ± 12.3 days vs. 16.9 ± 10.6 days, P = 0.041). High serum LDH levels were associate with higher risk for AKI (OR 1.82, 95% CI 1.16-2.84, P = 0.009, overall P < 0.001). There were no significantly interaction between LDH and CPK for mortality and AKI. Conclusions: Higher serum LDH levels are significantly prognostic factors for in-hospital mortality, AKI, and hospital duration.