While delta-8 THC products are used without legal regulation in the United States and other countries, they are legally controlled in South Korea. The types of evidence submitted to the Seoul Institute of National Forensic Service include seized materials, urine, and hair. In this study, we analyzed the results of delta-8 THC-related results from 2021 to June 2023 for seized materials and urine, and from 2022 to June 2023 for hair samples. In total, delta-8 THC was detected in 324 seizures, with the majority of cases (284) containing both delta-8 and delta-9 THC. 33 cases containing delta-8 THC alone, and 7 cases containing delta-8 THC, delta-9 THC, and synthetic cannabinoids. In cases where delta-8 THC was detected alone, the most common evidence type was jelly (14 cases), followed by e-cigarettes. In cases where both components were detected together, e-cigarettes were the most common. There were a total of 83 cases where delta-8 THCCOOH was detected in urine. Among of them, delta-8 THCCOOH was detected alone in 3 cases, while delta-8 THCCOOH and delta-9 THCCOOH were detected together in 75 cases. We analyzed the cases where delta-8 THCCOOH was detected in hair samples. A total of 83 cases were positive, with 16 cases detecting only delta- 8 THCCOOH and 67 cases detecting both delta-8 THCCOOH and delta-9 THCCOOH.