Fe2SnSe4 belongs to the adamantine family of quaternary chalcogenides crystallizing in the olivine type structure, which can be described from a hexagonal close-packing of selenium anions with the octahedral and tetrahedral sites occupied by the iron and tin cations, respectively. The structural characterization of the sample, synthesized by the melt and annealing technique, was carried out by powder X-ray diffraction at room temperature. The XRD data analysis shows, that Fe2SnSe4 adopt the orthorhombic olivine type structure, space group Pnma, and unit cell parameters a = 13.2019(3) Å, b = 7.6746(1) Å, c = 6.3572(1) Å, V = 644.11(2) Å3 were derived.