Radicular cysts arising from deciduous teeth are rare and usually cause a large bony defect. Autologous platelet-rich fibrin (PRF) is an easily available healing biomaterial in oral surgical defect with the new perspective of accelerated healing of a large bony defect. The present case is of unusually large radicular associated with neglected carious mandibular deciduous second molar in 10-year-old girl and its surgical management with PRF augmentation as a healing biomaterial in the bony defect. One-year follow-up showed uneventful healing and eruption of succedaneous tooth. Healing was relatively faster and facilitated by PRF placement. Furthermore, the importance of anticipatory guidance about the treatment of diseased primary teeth and their preservation gets highlighted.