The cereal grain crops have strong flexibility against adverse environment and they have various functional compounds. The objective of the present study was to screen phenolic compounds in sorghum [Sorghum bicolor (L.) Moench], foxtail millet (Setaria italica), common millet (Panicum miliaceum L.) by high performance liquid chromatography (HPLC) with photodiode array (PDA) detector. Sorghum contained the highest amount of phenolic compounds among three different crops (sorghum, foxtail millet, common millet). Especially Moktaksusu showed the highest amount of phenolic compounds concentrations and biggest regional differences. The comparison of average phenolic compounds in sorghums by regions showed order to Milyang ($963.3;{mu}g{cdot}g^{-1}$), Yeongyang ($923.1;{mu}g{cdot}g^{-1}$), Gijang ($831.3;{mu}g{cdot}g^{-1}$) and Bonghwa ($735.6;{mu}g{cdot}g^{-1}$). Among the sorghum cultivars, Moktaksusu ($1407.9;{mu}g{cdot}g^{-1}$) had the highest concentration of phenolic compounds. The average phenolic compounds of foxtail millets showed similar amount among Milyang ($319.0;{mu}g{cdot}g^{-1}$), Gijang ($288.1;{mu}g{cdot}g^{-1}$) and Bonghwa ($281.9;{mu}g{cdot}g^{-1}$) areas. The phenolic compounds of Yeongyang ($246.6;{mu}g{cdot}g^{-1}$) slightly low and that showed similar concentrations among three different regions. The concentration of phenolic compounds in foxtail millets, Chungchajo ($335.6;{mu}g{cdot}g^{-1}$) showed the highest concentrations. The average phenolic compounds of common millets showed the highest concentrations in Milyang ($305.5;{mu}g{cdot}g^{-1}$), Bonghwa ($262.0;{mu}g{cdot}g^{-1}$), Gijang ($195.1;{mu}g{cdot}g^{-1}$), Yeongyang ($237.2;{mu}g{cdot}g^{-1}$) in decreasing order. The concentration of phenolic compounds of common millets was the highest in the Norangchalgijang ($337.0;{mu}g{cdot}g^{-1}$), Hwanggumgijang ($250.0;{mu}g{cdot}g^{-1}$) was also relatively higher than others. The results of this study will provide basic information for breeding sorghums, foxtail millets and common millets with higher phenolic compound concentrations.