Background/aim: The aim of our study was to determine the usefulness of the Centor score and some basic laboratory tests (complete blood count and C-reactive protein) for the differential diagnosis of exudative tonsillitis due to Group A β-hemolytic streptococcus (GABHS) or due to non-GABHS agents. Materials and methods: The data of clinical and laboratory characteristics of the patients diagnosed with exudative tonsillitis were collected and statistically compared between those having positive GABHS throat culture result and those who were negative for any bacterial agent. Results: Totally 899 adult patients were included in our study; 56 (6.2%) of them were positive for GABHS, while 34 (3.8%) of the cases had a bacterial cause other than GABHS. The remaining 809 (90%) were accepted as non-GABHS cases. The percentages of patients having Centor score of 3 or greater, neutrophilia, lymphocytopenia, and CRP values of greater than 5-fold normal upper reference range were significantly higher in GABHS patients. Conclusion: Centor score of 3 or more together with high CRP, neutrophilia, and lymphocytopenia is predictive for GABHS tonsillopharyngitis.