The prevention and early detection of cervical cancer is achieved through women's regular use of Pap tests. Ascertaining adherence to Pap screening guidelines is often based on self-report, which may be unreliable. This study examined the reliability of Pap test self-reports and one potential source of error in them. We predicted that women having any gynecological examination (other than Pap tests) would falsely report having had a Pap test more often than women who had not experienced gynecological procedures. We compared self-reported Pap test utilization with medical records among 161 low-income women. Women with no Pap test in their medical record but who had experienced other gynecological procedures falsely reported a Pap test significantly more often than those women who actually received a Pap test or who had not received any gynecological procedure. Confusion over what type of gynecological procedures these women received could result in their under-utilization of Pap tests. Further, these findings question the validity of study findings based only on self-reported outcomes.