V4AlC3, a new MAX phase, was synthesized by reactive hot pressing of a V, Al, and C powder mixture at 1700 degrees C. Using a combination of Rietveld refinement with X-ray diffraction data and ab initio calculations, the crystal structure was determinated. It was found that V4AlC3 has a Ti4AlN3-type crystal structure. The lattice constants are a=0.29310 nm and c=2.27192 nm. And the atomic positions are V1 at (4f) (1/3, 2/3, 0.0544), V2 at (4e) (0, 0, 0.1548), Al at (2c) (1/3, 2/3, 1/4), C1 at (2a) (0, 0, 0), and C2 at (4f) (2/3, 1/3, 0.1080).