The presence of viral DNA in breast cancer cells is controversial. However, some studies have revealed apossible role for the human papillomavirus in the pathogenesis of breast cancer. The aim of the present studywas to investigate the presence of HPV-DNA in breast tissue in a group of Iranian women with and withoutbreast cancer and identification of the detected HPV types. Paraffin-embedded specimens from 65 malignantbreast cancer cases and 65 cases with benign breast lesions were investigated for presence of HPV-DNA by nestedpolymerase chain reaction. We found HPV-DNA in 22 (33.8%) of the breast cancer specimens. All non-cancerousspecimens were negative. Low and high-risk HPV types, including HPV-6 (26.2%), HPV-16 (1.5%), HPV-35(1.5%), HPV-52 (1.5%), and HPV-11 (1.5%) were detected in our study. HPV-6 was the most prevalent typein the breast cancer specimens. Although high-risk HPV types have been shown to have a major role in cervixcancer, there have been no data that support the same relevance for other types of malignancies. Furthermore,presence of low-risk HPV types in malignancies still is a matter of debate. The data presented in this studyindicates a strong need for epidemiological studies correlating different HPV types in human breast cancer.