Despite the recent attention to patient safety and quality of care, no prior studies have addressed outcomes of hospitalization for pneumonia among patients with schizophrenia. This study investigated the extent to which clinical outcomes of pneumonia were different among patients with schizophrenia. This study used data from the Taiwan National Health Insurance Research Database. Of the total of 81,599 patients admitted with a principal diagnosis of pneumonia from 2002 to 2004, 949 had previously been admitted with a principal or secondary diagnosis of schizophrenia within the 2 years of their index pneumonia admission. We randomly selected 2847 pneumonia patients matched with the study group in terms of gender, age, year of admission, length of stay, and Charlson Comorbidity Index score as the comparison cohort. Conditional logistic regression models were used for analysis. Findings indicated a higher prevalence of adverse outcomes among patients with schizophrenia. Patients with schizophrenia were independently associated with a 1.81 times greater risk of intensive care unit admission (95% confidence interval [CI] = 1.37-2.40), a 1.37 times greater risk of acute respiratory failure (95% CI = 1.08-1.88), and a 1.34-fold greater risk of mechanical ventilation (95% CI = 1.04-1.92) after adjusting for characteristics of patients, physicians, hospitals, and potential clustering effects. Adjusted odds ratios were further evident among those treated in private hospitals and in regional/district hospitals. Significant barriers to prompt and appropriate medical care for pneumonia persist for patients with schizophrenia. Careful monitoring of physical health and proper integration between psychiatrists and physicians should be stressed to reduce poor clinical outcomes in this vulnerable population.