Background: Lentigo maligna (LM) often displays extensive subclinical spread. Mohs micrographic surgery (MMS) has been proposed to help delineate the true histologic margin; however, visualizing atypical melanocytes on frozen section is challenging and often requires confirmatory permanent paraffin sections. Objective: Our aim was to use a monoclonal antibody to rapidly stain frozen sections during MMS to facilitate better visualization of atypical melanocytes. Methods: Frozen sections of LM during MMS were stained with MART-1 (melanoma antigen recognized by T cells) and compared with paraffin-embedded sections. Results: We found 100% correlation between frozen sections stained with MART-1 and paraffin-embedded sections. Conclusions: Atypical melanocytes can be better visualized on frozen sections of LM by using MART-1 rather than hematoxylin and eosin. This allows for easier identification during MMS and better chance of complete removal of LM lesions. (J Am Acad Dermatol 2002;46:78-84.)