Although only a small proportion of invasive squamous carcinoma of the cervix present with microinvasive disease, consistent recognition of this entity is important because it carries important management implications. The objective of this review was to reassess the methods and criteria for a histopathologic diagnosis of both early invasive squamous and adenocarcinomas in light of recent pathologic and clinicopathologic studies. The diagnosis of microinvasion is primarily histopathologic. Although the concept of microinvasion initially seems obvious, there are problems in diagnostic precision. A clear understanding of both the Society of Gynaecologic Oncologists' and the International Federation of Obstetricians and Gynecologists' classifications of early invasive disease is required. Subsequently, key parameters must be assessed-measurement of depth and lateral spread, assessment of margins, and identification of lymphovascular invasion-using accepted reference points and definitions. This assessment requires properly oriented and stained histologic sections of a loop electrosurgical excision procedure or cone specimen. Immunohistochemical staining of vascular endothelium or epithelial basement membrane has only a limited/adjunctive role. Controversy continues regarding the need to appraise the extent of any lymphovascular invasion and measurement in cases with multifocal invasion. Application of criteria to invasive adenocarcinomas seems warranted but is particularly challenging because of its special morphology and different biology.