Cervical dysplasia, or cervical intraepithelial neoplasia (CIN), is a premalignant precursor to cervical cancer. This study was designed to determine whether dysplastic lesions are angiogenic. Tissue sections from 23 surgical specimens were immunohistochemically stained for factor VIII antigen, a marker for endothelial cells. The results demonstrate that a region of neovascularization develops along the basement membrane subtending dysplastic epithelium when compared to adjacent normal epithelium. Comparison of microvessel counts underlying low grade lesions (condyloma and CIN I) with microvessel counts of CIN III lesions shows a statistically significant increase in the more advanced lesions. In a subset of the high grade lesions, large vascular structures are also noted in the upper layers of the epithelium, suggesting that a second stage of neovascularization consists of extension of stromal vascular papillae into the dysplastic lesions toward the surface of the epithelium. There is no statistical correlation between the amount of inflammation and the angiogenic ratio for each lesion, implying that angiogenesis is not secondary to the inflammatory response evoked by the lesion. The human papillomavirus type present in four CIN III lesions was determined by in situ hybridization; the amount of angiogenesis appears to be independent of the human papillomavirus type.