Complete resection with minimal sacrifice of healthy skin is the goal in treatment of basal cell carcinoma (BCC) of the face. In a randomized trial, preoperative assessment of tumor extension with the Varioscope, a combination of microscope and loupe glasses with strong illumination and a maximal magnification of 7X, was compared with tumor assessment without. Forty consecutive, primary BCC of the solid subtype of the face were randomly assigned to the study groups. Preoperative tumor marking was done by a surgeon not involved in tumor resection, reconstruction, and patient follow-up. All BCC marked with the high magnification were completely excised in the first resection. In the control group, frozen section was used in 12 tumors and permanent section in the remaining 8. The first resection did not yield tumor-free margins as assessed in the frozen section analysis in 3 tumors. In 2 of 8 tumors not supported by frozen section analysis, incomplete excision was detected, and 1 case of false-negative frozen section analysis occurred. In conclusion, the use of high magnification resulted in a trend towards reduction of positive tumor margins in the subgroups that were performed under either intraoperative frozen section or permanent, fixed section histology control, and a significant reduction in tumor-positive margins of all first resections. This was attributed to enhanced preoperative tumor visualization by high (7X) loupe magnification and additional lighting