Changes in vascular patterns aid in the colposcopic diagnosis of cervical neoplasia. We have studied vessels in 50 cases of normal cervix, cervical intraepithelial neoplasia (CIN I, II, III), and invasive carcinoma by two markers, Von-Willebrand factor (VWF) and ulex europaeus lectin I. With both markers, an increase in microvessel counts parallel to neoplastic progression was seen, with highest counts observed in CIN III. Average counts for ulex lectin and VWF increased from approximately 6 vessels per field in normal cervices to 15 vessels per field in CIN III. For each diagnostic group, comparable numbers of vessels were stained by both markers, with a slight preponderance of VWF in invasive carcinomas and of ulex lectin in noninvasive lesions. No correlation was found between microvessel count and human papilloma virus (HPV) by in situ hybridization. We conclude that enhanced microvessel density occurs in cervical neoplasia. The vessels are mostly blood vessels, not lymphatics. Therefore, the role of enhanced microvessel density in tumor spread remains to be proven.