In temperature interval T=4.2 290 K in polycrystalline substance-2-hydroxy-1-nitrozonaphathalene Na[Fe(C10H6 ONO)(3)], the EPR spectrum of Fe3+ has been investigated. The EPR spectrum is a superposition of two resonance lines and the non-resonance absorption. At the temperature change the redistribution of the absorption between the resonance lines takes place. The resonance line 1 with the effective g-factor g(1) =4.32+/-0.02 has a maximal intensity at T=4.2 K. The resonance line 2 with the effective g-factor g 2 =2.00+/-0.01 has the maximal intensity at T=290 K. With rising of temperature the integral intensity of the line 1 is decreasing, whiledivided by intensity of the line 2 increasing. The second peculiarity of the temperature changes in the EPR spectrum of Fe3+ in the Na[Fe(C-10 H6ONO)(3)] is the exponential increasing of the linewidth for resonance line 2 when the temperature is lowered. The properties of EPR spectrum manifested in complex of iron with 2-hydroxy-1-nitrozonaphathalene are characteristics of the magnetic centers with multiple-minimum potential.