Single crystals of SmCu4Ga8 have been grown using Ga flux and characterized by single-crystal X-ray diffraction. SmCu4Ga8, isostructural to SmZn11, crystallizes in the hexagonal P6/mmm (No. 191) space group, with Z = 3 and lattice parameters a = 8.865(2) angstrom and c = 8.607(2) angstrom. Magnetic susceptibility data show antiferromagnetic ordering at 3.3 K. Metallic behavior is observed in the temperature range 2-300 K. A large positive magnetoresistance (MR% = (rho(H) - rho(0))/rho(0) x 100) up to 40% is also observed near T-N. In this paper, we present the structure and physical properties of SmCu4Ga8.