Single crystals of the compound {NH2(C2H5)2}2[(UO2)2C2O4(CH3COO)4] · 2H2O (I) are synthesized, and their structure is investigated using X-ray diffraction. Compound I crystallizes in the monoclinic system with the unit cell parameters a = 9.210(2) Å, b = 14.321(3) Å, c = 12.659(3) Å, β = 105.465(13)°, V = 1609.2(6) Å3, space group P21/c, Z = 2, and R = 0.0198. The structural units of crystals I are binuclear groups of the composition [(UO2)2C2O4(CH3COO)4]2− with an island structure, which belong to the crystal-chemical group A2K02B401 (A = UO22+, K02 = C2O42−, B01 = CH3COO−) of the uranyl complexes, diethylammonium cations, and water molecules. The uranium-containing groups are joined into a three-dimensional framework through electrostatic interactions with diethylammonium cations and a system of hydrogen bonds, which are formed with the participation of the atoms involved in the composition of the water molecules, oxalate ions, acetate ions, and diethylammonium cations.