Human papilloma virus (HPV) DNA sequences have been detected in paraffin-embedded tissue using an enzymatic in vitro amplification technique known as the polymerase chain reaction. Amplification of a HPV DNA sequence before its detection with a cDNA probe significantly increases the rapidity as well as the sensitivity of detection such that a single 5-10-micron thick paraffin-embedded tissue section can be analyzed within 24 h. The assay specifically detected HPV 16 or 18 without crossreactivity with HPV 6 or 11. As few as 20 viral copies could be detected. The rapid and sensitive analysis of HPV in normal and pathological tissues using this technique may contribute significantly to identifying the role of HPV as a risk factor in carcinoma.