Lithium alloys continue to be promising materials for anodes of chemical current sources, so the search for new lithium-containing intermetallic phases and the study of their crystal structure were the task of our study. In continuation of the study of the Li–Cu–Ga system, two alloys of Li 2 CuGa and LiCu 2 Ga were synthesized. The alloys were synthesized in an electric arc furnace in an atmosphere of purified argon from portions of pure components (content of the main component: Lithium ≥ 99.8 wt. %, copper and gallium ≥ 99.99 wt. %). The alloys were homogenized at 200 °C for two months in tantalum containers sealed in evacuated quartz ampoules. After annealing, the alloys were stored under a layer of purified and dehydrated paraffin oil. X-ray powder diffraction patterns from the synthesized alloys were obtained on a powder diffractometer DRON-2.0 M (Fe Kα -radiation). By comparing the obtained diffractograms with previously studied alloys, it was assumed that the compounds Li 2 CuGa and LiCu 2 Ga will be isostructural with the phases Li 2 AgIn and LiAg 2 In. Based on these models, the crystal structure was refined by the Rietveld method: Li 2 CuGa, (Li2AgSb, F –43 m , a = 6.0942 (7) Å; R Br = 0.0789, R F = 0.0482); LiСu 2 Ga (Cu 2 MnAl, Fm –3 m , a = 5.8964 (8) Å; R Br = 0.0711, R F = 0.0311). In the Li–Cu–Ga system, two ternary compounds are formed with the ratio of components 2:1:1 and 1:2:1, which is quite interesting because Li, Cu and Ga atoms differ greatly by nature ( s -metal, d -metal and p -metal) and size (metal radii: Li – 1.52 Å; Cu – 1.28 Å; Ga – 1.35 Å). Nevertheless, in the structures of both compounds all atoms have a similar coordination of atoms - rhombododecahedron and identical values of interatomic distances: in the structure of the compound Li 2 CuGa eight distances with a length 2.6389 Å and six distances – 3.0471 Å; in the structure of the LiCu 2 Ga compound there are eight distances with a length of 2.5532 Å and six distances with a length of 2.9482 Å. Keywords: lithium, copper, gallium, X-ray powder diffraction method, crystal structure.