Most of the general literature indicates that water containing ions is more efficiently heated by microwaves in comparison to pure (deionized) water (Gabriel et al., 1998) but one report (Metaxas, 1996) points out that microwaves of different frequency regions are needed to create oscillation in ions and rotation in polar molecules. Thus, microwaves of certain frequency band cannot produce heat simultaneously by both mechanisms. There are some reports that indicate less heating in the case of the presence of ions in water. Ponne (1996) developed microwave penetration profiles, calculated by Quasi-optical method, in pure water and 4% NaCl solution and found that microwave penetration depth significantly decreased in NaCl solution. Keiko (2003) studied the effect of concentration of sodium chloride on the heating efficiency of microwave and found that the solution was not efficiently heated in the microwave oven. Hasted (1973) found that at higher salt concentrations, the ions orient the water molecules around them, which lessen the ability of water molecules to adjust in the applied electric field, reducing the dielectric constant and thus, less heat is produced.