Magnetic interaction of the magnetite (Fe3O4) nanoparticles grown on zeolite has been studied. XRD patterns show that in the presence of 25-75 mg of zeolite the average particle size of Fe3O4 decreases to ≈6 nm, but with the increase of zeolite content (75 mg<x<200 mg) the Fe3O4 particles have 10.6 nm in size saturating to 3 nm above 180 mg. Average hyperfine field of Fe at octahedral and tetrahedral sites vary with particle size. With the increase of zeolite 13x from 0 to 100 mg, the saturation magnetization decreases from 63 to 53 emu/g. Mössbauer studies show the presence of different Fe3O4 microenvironments, possibly in pores and on the surface of zeolite. Transformation of the superparamagnetic doublet to sextet at 80 K can indicate a variation in the magnetic interaction. At low temperature the interaction between Fe3O4 at the pore and at the surface enhances the magnetic ordering. The nanoparticles in the pores of zeolite are connected with the surface particles in low zeolite content and get isolated as the amount of zeolite increases.