BACKGROUND Human papillomavirus (HPV) plays a major role in the etiology of many malignancies of diverse localization, such as uterine cervical carcinoma and its precursors. Human papillomavirus sequences have been detected throughout the male lower genitourinary tract, but the role of men as transmitters remains unclear. OBJECTIVE To investigate the relationship between azoospermia and the presence of HPV DNA in testicular cells. METHODS One hundred eighty-five patients with azoospermia undergoing testicular biopsy were studied. Histologic study was done on formalin-fixed, paraffin-embedded samples from testicular biopsies, stained with hematoxylin-eosin. Molecular study to detect HPV sequences was performed on genomic DNA isolated from paraffin sections by standard protocols. Seven cases containing HPV sequences were studied after microdissection with PALM microlaser technology in order to determine the presence of HPV DNA sequences in different cells, as well as from seminal tubules or stromal (Leydig) cells. RESULTS Human papillomavirus DNA sequences were detected in testicular biopsies of 12 patients (6.48%). Human papillomavirus type 16 was the most common genotype encountered. Among the 92 patients who underwent bilateral testicular biopsy, HPV sequences were detected in 9 patients (9.78%), all of whom showed only unilateral testicular affection, more often in the left testicle (ratio, 2: 1). After microdissection, HPV DNA sequences were seen in Leydig and Sertoli cells; the presence of HPV in germinal cells could not be ruled out. CONCLUSIONS Leydig cells, Sertoli cells, and probably germinal cells (cases 2, 3, and 4) harbored HPV DNA sequences. Such findings have not been previously described in testicular tissue.