Clinical prediction indicators such as the pneumonia severity index (PSI) and CURB-65 score are useful, but they are complex and often not followed. Therefore, biomarkers that improve hospital outcome predictions are emerging. This study evaluated the prognostic value of a new sepsis biomarker, serum lysophosphatidylcholine (LPC) concentrations, in community-acquired pneumonia (CAP) patients. We prospectively collected blood samples from emergency department CAP patients on days 1 and 7 (post-admission) and analyzed their plasma LPC concentrations. We retrospectively reviewed patient medical records and analyzed correlations between plasma LPC concentrations and clinical parameters and hospital outcomes. A total of 56 CAP patients were included in this study; 24 (42.9 %) required intubation and 15 (26.8 %) died. The mean LPC concentrations on days 1 (p = 0.015) and 7 (p = 0.002) of hospitalization were significantly lower in the non-survivors. Day 1 LPC concentrations were inversely correlated with the PSI (ρ = -269) and CURB-65 scores (ρ = -386). For predicting hospital mortality, the day 1 LPC concentration was comparable with the CURB-65 or PSI scores. Day 1 LPC cut-off levels <29.6 μmol/L were associated with hospital CAP outcomes, including the need for mechanical ventilation, vasopressors, intensive care unit admission, and hospital mortality. Additionally, day 7 LPC concentrations were correlated with in-hospital mortality. Initial serum LPC concentrations predicted hospital outcomes in CAP patients requiring hospitalization. These values were correlated with prognostic markers, such as the PSI and CURB-65 scores. Additionally, follow-up LPC measurements predicted the clinical course of CAP patients.