A patient with a large periapical lesion around the apices of her mandibular incisors is presented. During the conservative non-surgical endodontic treatment, sodium hypochlorite was used for irrigation, and calcium hydroxide was used for the intra-canal dressing. Periapical healing was observed 1 month after obturation and continued in the 12-month recall. This report confirms that the large size of a periapical lesion does not mandate its surgical removal, and that even cyst-like periapical lesions heal following a conservative endodontic therapy.