In this application, we describe a technique for the monitoring of six cannabinoids, including THC and CBD, in hemp seed oil by HPLC with PDA detection. Figure 1 shows the chemical structures for the six cannabinoids. In recent years, scientific knowledge regarding the composition and health benefits of edible hemp products has significantly increased. Hemp seed oil has been promoted as a good source of nutritious omega-6 and omega-3 polyunsaturated acids, and may be a cleaner, more sustainable alternative to fish oil.