There are well established admission criteria for patients suffering from community-acquired pneumonia, yet the clinical tool for decision to discharge the hospitalized patient is lacking. Continuous pressure to reduce hospital expenditures can lead to a premature discharge of unstable patients. The current study assessed the impact of clinical instability at discharge on short-term outcomes. Demographic data, background disease, laboratory tests results and PORT score were assessed prospectively. On the last day of the hospitalization 7 physiological parameters of instability were evaluated. 60 d composite mortality and readmission rate was a primary outcome measure. Of the 373 patients, 22% were discharged with 1 or more instabilities, of whom 26.8% reached primary outcome within 60 d, compared to 8.2% of patients with no instabilities. 60 d death rate was 2.1% in the former group, compared to 14.6% in the unstable patients (p<0.001). Instability on discharge remained a significant prognosticator of adverse outcome (odds ratio 3.5; 95% CI 1.8-6.8) after adjustment for pneumonia severity and baseline comorbidity. We concluded that discharging an unstable patient hospitalized with pneumonia is associated with elevated risk of death or readmission within 60 d. Pneumonia guidelines should include objective criteria for judging patients' stability and promptness for discharge.