As the seizures of cannabis have risen since 2018, the presumptive identification of THC has been studied to determine the presence of THC in seized cannabis using color tests. Because the color tests are simple to perform, inexpensive and give results that can be viewed by the naked eyes, four different color tests were examined in this study. Duquenois- Levine reagent, Fast blue B salt, Fast blue BB salt and 4-Aminophenol were compared to detect THC in the Cannabis specimens. The seized cannabis flowers were used as specimens and four reagents of Duquenois-Levine, Fast blue B salt, Fast blue BB salt, 4-Aminophenol were prepared according to the guidelines of the UNODC. GC-MS was utilized to measure the LODs of THC for the color tests applied. Duquenois-Levine, Fast blue B salt, Fast blue BB salt and 4-Aminophenol showed distinctive color changes in the presence of cannabis. By Duquenois-Levine, the color changed to blue-violet, Fast blue B salt to purple-red color, Fast blue BB salt to reddish orange color and 4-Aminophenol to blue. The LODs of THC by the four reagents were as follow: Duquenois-Levine and 4-Aminophenol showed 2 μg, Fast blue B salt was 0.6 μg and Fast blue BB salt was 0.8 μg. It was interesting to note that the blue color by 4-Aminophenol indicated the presence of THC, while pink color indicated the presence of CBD. In conclusion, Fast blue B salt was the most applicable color test to determine the presence of cannabis with the lowest LOD of THC.