An experimental comparative analysis of series and parallel antennas was performed in an inductively coupled plasma. For the quantitative comparison of series and parallel antennas on the plasma generation, both antennas were made of copper tubes of the same length and thickness. The power transfer efficiency and the electron energy distribution function were measured. The experimental results show that the series antenna generates higher density plasma due to high coupling at the same applied powers (RF powers), while the parallel antenna generates higher density plasma due to low plasma potential (low ion energy losses) at the same absorbed powers. This provides practical information on plasma generation efficiency according to the antenna configuration of the ICP.