Systemic inflammatory response syndrome (SIRS) reportedly has a low performance for distinguishing infection from non-infection. We explored the distribution of the patients diagnosed by SIRS (SIRS patients) or a quick sequential organ failure assessment (qSOFA) (qSOFA patients) and confirmed the performance of the both for predicting ultimate infection after hospital admission. We retrospectively analyzed the data from a multicenter prospective study. When emergency physicians suspected infection, SIRS or the qSOFA were applied. The area under the receiver operating characteristic curves (AUC) was used to assess the performance of the SIRS and qSOFA for predicting established infection. A total of 1,045 patients were eligible for this study. The SIRS patients accounted for 91.6% of qSOFA patients and they showed a higher rate of final infection than that of non-SIRS patients irrespective of the qSOFA diagnosis. The AUCs for predicting infection with SIRS and a qSOFA were 0.647 and 0.582, respectively. The SIRS significantly predicted an ultimate infection (AUC, 0.675; p = 0.018) in patients who met the SIRS and qSOFA simultaneously. In conclusion, the SIRS patients included almost all qSOFA patients. SIRS showed a better performance for predicting infection for qSOFA in those who met both definitions.