<p>Acute on chronic mastoiditis is a recognized complication of otitis media in children; however, bilateral postauricular abscess formation is extremely rare, particularly in infants. A one-year-old child presented with bilateral ear discharge for six months and progressive swelling behind both ears for two weeks. Clinical and radiological evaluation revealed bilateral postauricular abscess secondary to acute on chronic mastoiditis. The child underwent bilateral incision and drainage, and pus was sent for culture and sensitivity. Culture-directed antibiotic therapy was administered, resulting in complete clinical resolution. This case highlights the rarity of bilateral postauricular abscess in infancy and emphasizes the importance of early diagnosis, prompt surgical intervention, and appropriate antibiotic therapy in complicated mastoiditis.</p>