In soybean (Glycine max (L.) Merr.) seeds, phosphorus (P) is primarily stored in the form of phytate, which is generally indigestible by monogastric animals such as human, pig, poultry, and fish. Thus, this study was conducted to isolate soybean mutants with high available P. Inorganic P content was assessed in a total of 1,266 ethyl methanesulfonate (EMS) M4 lines from the Pungsannamul cultivar. Among the tested lines, four EMS lines (PE379, PE432, PE2205, and PE2503) showed higher mean inorganic P (1.21-1.56 g kg-1) than did the Pungsannamul cultivar (0.90 g kg-1). Additionally, six EMS lines (PE718, PE828, PE1466, PE1552, PE3378, and PE3386) showed lower mean inorganic P (0.38-0.60 g kg-1). The high inorganic P mutants isolated in this study will be further investigated for phytate and total P levels. Moreover, the high and low inorganic P lines will be utilized in a future study of the biochemical pathway of phytate.