Innovative approaches such as online, at-home programs may address important barriers to sexually transmitted infection (STI) and human immunodeficiency virus (HIV) screening in the United States. This study evaluated the first year of an online, at-home program offering HIV and triple-site (urogenital, rectal, and pharyngeal) gonorrhea (GC) and chlamydia (CT) testing in Colorado. Test Yourself Colorado (TYC) is an online, at-home program that provides free mailed HIV tests and/or GC/CT tests to Colorado adults. Program use and outcomes between 1 June 2021 and 31 May 2022 were analyzed. A total of 1790 unique clients utilized TYC. Of 1709 clients who ordered HIV tests, 508 (29.7%) were men who have sex with men (MSM), and 41.3% (210/508) of these clients reported having never been tested for HIV before or were not tested in the prior year. Hispanic clients had lower STI test return rates (37.1%; 134/361) compared with non-Hispanic clients (45.9%; 518/1128) (P = .003). Positive STI tests were identified in 9.6% (68/708) of clients. Positive STI tests were more common in MSM clients (15.7%; 34/216) compared with all other sexual orientations (6.9%; 34/492) (P < .001). STI treatment was confirmed in 80.9% (55/68) of clients. The TYC online, home testing portal is a scalable tool that reaches clients at risk of STIs and HIV and navigates those with positive STI tests to treatment. HIV/STI home testing programs need to further assess and address utilization and outcomes for disparities by race and ethnicity to assure programs equitably benefit all at-risk communities.