The purpose of this report is to discuss the case of a four-year-old African-American girl who presented with clinical and radiographic evidence of localized stage III grade C periodontitis. She had no history of systemic disease or caries. Treatment consisted of oral hygiene instructions, extraction of unsalvageable teeth, full-mouth debridement with the use of systemic antibiotics and subsequent periodontal maintenance care. The patient underwent a two-year follow-up, during which the disease was stabilized and no space loss was detected. Although this condition is uncommon, the pediatric dentist must be able to diagnose and treat periodontitis in the primary dentition early, together with a multidisciplinary team, to prevent a recurrence of this disease in the permanent dentition.