Case seriesPatients: Male, 20 • Male, 4 • Male, 27 • Male, 25 • Female, 5 • Female, 26Final Diagnosis: Post tonsillectomy secondary hemorrhageSymptoms: Bleeding • bleeding per oralMedication: —Clinical Procedure: Control of post tonsillectomy secondary hemorrhageSpecialty: OtolaryngologyObjective:Rare diseaseBackground:Post-tonsillectomy hemorrhage (PTH) has been reported in the literature as a serious complication after tonsillectomy that has high morbidity and can be life threatening. In cases of recurrent secondary PTH, one should consider coagulopathies as the hidden pathology. Factor XIII deficiency is very rare, suggested to be present 1 in 2 million people. Patients with undiagnosed factor XIII deficiency with secondary PTH are extremely rare.Case Report:We report on the cases of six patients (four adults and two children) who presented with recurrent attacks of secondary PTH.Conclusion:Recurrent, severe PTH could be related to undiagnosed hematological disorders.