The incidence of mastoiditis in pediatric age has consistently increased over the last two decades due to increase of antibiotic-resistant bacteria. Compared to young patients, occurrence of acute otitis media complications such as acute mastoiditis and subperiosteal abscess is relatively low in adults. Various treatments for acute mastoiditis with subperiosteal abscess such as tympanostomy tube insertion, intravenous antibiotics, and postauricular incision and drainage have avoided the morbidity and necessity of mastoid surgery. Recently, many studies have indicated mastoidectomy only in cases of severe complications or failure of disease improvement after antibiotic treatment and myringotomy. In this report, we present two cases of successful treatment of subperiosteal abscess and discuss the management of acute mastoiditis with subperiosteal abscess in both child and adult.