Background: In this study a series of BASIC dosimetric proper es of a lowDENSITY (LD) gel dosimeter are inves gated. The dose response is studied regarding to linearity, sensi vity, dose-rate AND energy dependence as well as lung ssue equivalence. Materials AND Methods: The LD gel was made by mixing the polymer gel with expANDed polystyrene spheres. Energy dependence was studied at two different energies: 1. 25 MeV AND 6 MV photon beams which were produced by 60Co AND Linac machines. Inves ga on of dose rate dependence was performed in the low, medium, AND high absorbed dose regions. Also reproducibility of dose response was studied in three sets of LD gel with iden cal prepara on, irradia on AND imaging procedure at three different days. Moreover the linearity AND sensi vity were inves gated up to 30Gy. Results: The results showed that the dose response was reproducible. The gel response was found linear up to 22Gy with r2=0. 981 AND sensi vity of 0. 814S-1Gy-1. In the measured ranges, the dose response of LD gel was independent of beam energy within less than ± 0. 02 AND dose rate had no effect on the gel response. LD gel was nearly lung ssue equivalent with mass DENSITY 0. 37 to 0. 4g/cm3 AND rela ve electron DENSITY 0. 41. Conclusion: MAGAT LD gel dosimeter appears to be a promising dosimeter in all aspects of dosimetric proper es evaluated in this study. In addi on, its high linearity together with no dose rate dependence in different level of absorbed doses makes it a suitable dosimeter to measure 3D-dose distribu ons inside a non-homogeneous media.