Atypical Junctional Melanocytic Hyperplasia (AJMH) is the precursor of lentigo maligna melanoma. Peripheral margin clearance of AJMH is problematic, as traditional pathologic evaluation of specimens can miss lesional extensions, and frozen sections and Mohs' surgery are unreliable. Current practice involves treating defects with temporary skin grafts or local wound care, until pathologic evaluation is completed. This can result in desiccated and contracted wounds, making optimal aesthetic reconstruction difficult. The "square" technique allows peripheral margin control prior to lesion excision, thereby permitting immediate reconstruction. Patients with facial AJMH underwent geometric excision of peripheral margins under local anesthesia using double-bladed scalpels. Repeat "square" excision was performed until permanent sections revealed clear margins. Definitive excision and immediate reconstruction was then performed. Forty-six patients underwent margin control with "square" excision prior to definitive resection and immediate reconstruction of facial AJMH. The mean number of procedures required for margin clearance was 1.8 +/- 0.8 (range 1-5). The use of the "square" technique in the management of AJMH provides certainty of margin control prior to excision and reconstruction. Thus, reconstructive options can be pursued in a staged, elective manner, avoiding an intervening open wound, and providing for optimal aesthetic results.