In this paper we report the results of our study in which we compared lung density values obtained from EIT and CT values (HU) within a region of interest. The purpose was to verify clinical use of lung density estimation using EIT data. Image resolution of CT images, which was originally 512*512 pixels, was changed to 16*16 pixels, to match that of the EIT images. The CT and EIT images were recorded from eight patients in an intensive care unit and the results showed a correlation coefficient of 0.66 (p<0.05) between the CT values (HU) and the lung density values (kg/m3) obtained from EIT