Objectives: Characterisation of clinical manifestations in children who had acute mastoiditis (AM) -related intracranial complications (ICCs) and to determine the incidence of ICCs in the study group. To define children with a higher risk of ICCs and gain new information on aetiological microbial agents of AM. Methods: A retrospective analysis of 137 paediatric patients with AM treated at a tertiary centre using standard dia­gnostic and therapeutic protocol between 2002 and 2019. Results: Altogether 137 patients with AM were hospitalised at our centre between 2002 and 2019. During this time, the occurrence of ICC in children with AM was low (n = 3, incidence 2.19%). Due to the low number of patients with ICC with AM in our patient group, we were unable to define a specific group of patients with a higher risk of ICC development in AM. Despite this fact, the average value and median of CRP were considerably higher in patients with AM-associated ICCs. The most frequent aetiological agent was Streptococcus pneumoniae. Conclusions: The low incidence of ICC in patients with AM in our patient group might be caused by routinely performed paracentesis in developed acute otitis, rational antibio­tic therapy and the good availability of an ENT specialist in the Czech Republic. The most common aetiological agent of AM was Streptococcus pneumoniae. Keywords: Streptococcus pneumoniae – acute mastoiditis – intracranial complications – aetiological agent – antibio­tic therapy – antromastoidectomy