Objective: The authors describe the cervical cytology and sexually transmitted infection (STI) testing patterns of US college health centers. Participants and Methods: A total of 128 self-selected US college health centers--representing more than 2 million college students--completed an online survey during February and March 2007. Results: Almost 13% of cervical cytology results were abnormal; most of these were atypical squamous cells of undetermined significance and low-grade squamous intraepithelial lesions. In women, 2.9% of chlamydia tests and 0.4% of gonorrhea tests were positive. Human immunodeficiency virus (HIV) and syphilis tests were positive in 0.1% and 0.3% of students tested, respectively. Herpes simplex virus type 1 (HSV-1) accounted for 59.9% of genital herpes infections. Conclusions: College health centers are important sources for Pap and STI test data. Pap tests frequently yield low-grade abnormalities, and screening tests for chlamydia and especially gonorrhea are infrequently positive. Rates of HIV and syphilis in this population are low, raising concerns about positive predictive value when screening low-risk students. A majority of genital herpes infections are caused by HSV-1. (Contains 3 tables and 1 figure.)