We have used a polymerase chain reaction (PCR) to examine cervical cancer biopsy specimens and pelvic lymph nodes for the presence of human papillomavirus type 16 (HPV 16) DNA. Of the 75 cervical specimens tested, 36 (48%) were positive for HPV 16 in the PCR. A total of 65 pelvic lymph nodes removed during radical surgery on 35 women were also analyzed. Lymph nodes originating from 19 patients whose cervical biopsy specimens were negative for HPV 16 seemed to lack HPV 16 sequences. For 16 women with positive PCR results for cervical biopsy specimens, 9 of 10 lymph node metastases were positive in the PCR, while 11 of their 36 histologically negative lymph nodes were also shown to contain HPV 16 DNA.