Objectives: Rapid and accurate identification of persons infected with SARS-CoV-2 which causes COVID-19 is key to managing the pandemic. The urgent need to scale up access to COVID-19 testing in Nigeria has led to the government's introduction of the use of COVID-19 Ag rapid diagnostic test (RDT) across various settings in the country. However, field performance evaluation of the rapid SARS-CoV-2 antigen detection test is required to be conducted periodically and compared with the gold standard real-time reverse transcription-polymerase chain reaction (RT-PCR) test for diagnosis of COVID-19 cases. Design: A prospective COVID-19 screening and un-blinded verification of the performance of the STANDARD Q COVID-19 Ag test kit. Setting: The rapid SARS-CoV-2 antigen detection test, Standard TM Q COVID-19 Ag kit was compared with the RT-PCR test for detection of SARS-CoV-2 in nasopharyngeal samples for COVID-19 screening from persons and personnel attending a national youth camp orientation exercise during the second wave of the COVID-19 outbreak (January to March 2021) in Ondo state, southwest Nigeria. Participants: Three hundred fifty-one persons and personnel were screened for COVID-19 infection. Results: Of 351 respondents screened, 68 (19.4%) were positive, and 264 (75.2%) were negative for both COVID-19 Ag RDT and RT-PCR assay. The rapid SARS-CoV-2 antigen detection test's sensitivity and specificity were 78.16% (95% CI = 68.02% -86.31%) and 100.0%