The International Federation of Gynecologists and Obstetricians (FIGO) definition of microinvasive carcinoma of the cervix changed recently. We clinically reviewed our treatment of superficially invasive cancer of the cervix in Eight of those changes. The review covered all patients treated at the University of Michigan from 1970 to 1985 who had stage I squamous cell carcinoma of the cervix, with the Society of Gynecologic Oncologists (SGO) and new FIGO criteria for microinvasion used. Using SGO criteria, 43 patients were treated as follows: total abdominal hysterectomy (32), total vaginal hysterectomy (7), radical hysterectomy (2) and cone biopsy (2). One. patient, who had multifocal disease with a maximum depth of 1.5 mm, developed a recurrence and died of the disease. A review of 345 patients considered to have stage IB disease tinder SGO criteria showed 30 patients who were reclassified as having stage IA2. All these patients were treated with radical surgery and survived, and all had negative lymph nodes. Radical surgery for patients with move than microinvasion according to SGO criteria provides excellent survival rates. Radical therapy may also be indicated for multifocal lesions.