[en] Highlights: • RE₅Ru₃Ga₂ (RE = La, Ce, Pr, and Nd) crystallize with a cubic structure of the La₅Ru₃Al₂ type. • Upon small substitution of Al for Ga, a LT trigonal variant of Ce₅Ru₃Ga₂ can be stabilized. • LT-Ce₅Ru₃Ga_2−xAl_x of Ce₅Ru₃Al₂ structure type is characterized by very short Ce-Ru distances. • The cubic Ce₅Ru₃Ga₂ orders magnetically at T_C = 1.7 K. • Electrical conductivity of this material bears a Kondo lattice character. -- Abstract: Novel ternary gallides RE₅Ru₃Ga₂ (RE = La, Ce, Pr, and Nd) crystallize with a cubic structure of the La₅Ru₃Al₂ type (space group I2₁3) with the lattice parameters: a = 9.9082(3), 9.6926(4), 9.7509(5), and 9.7222(4) Å, respectively. Upon small substitution of Al for Ga (≤1 at% Al), the compound Ce₅Ru₃Ga_2−xAl_x can be stabilized as a low-temperature trigonal variant (space group R3). The latter phase, bearing the unit cell parameters a = 13.7892(3) Å and c = 8.3095(2) Å, is closely related to the Ce₅Ru₃Al₂ structure type. Its characteristic structural feature is the presence of very short interatomic Ce-Ru distances of 2.40(4) Å. The cubic Ce₅Ru₃Ga₂ exhibits Curie-Weiss paramagnetism with notably reduced effective magnetic moment. At T_C = 1.7 K, the compound orders magnetically, probably with a ferrimagnetic magnetic structure. The metallic-like electrical conductivity of this material bears a Kondo lattice character.