A new technic is described for more accurately checking the surgical margins of skin tumors removed by standard surgical excision. Vertical sections of surgical specimens represent check points of the margin only 7 μ thick. This means most of the surgical margin is not checked microscopically, allowing small tumor islands at the margin to remain undetected. The technic is applicable wherever surgical excision is used to excise skin tumors. It is especially suitable for basal cell carcinoma. A variable-width knife holding two scalpel blades parallel to each other is set at 2 to 3 mm separation. When the excision is done as usual, the blades will cut a 2- to 3-mm strip of tissue representing the entire lateral borders of the excision. This specimen is easily mounted as a flat section for frozen or paraffin processing. These sections will be cut to show the entire lateral excision margin to be checked for tumor. A new punch with concentric cutting edges separated by 2 mm has been made to obtain a similar flat section. The circular defect is converted to a standard ellipse and closed primarily. This technic has the advantage of using primary closure for excellent cosmetic results. It requires little additional skill on the part of the surgeon and is easily handled by the pathology laboratory. It has been used in thirteen cases with no recurrence of tumors to date. (J AM ACAD DERMATOL 7:495-499, 1982.)