Vanadium nanoparticles of two sizes were fabricated by pulse laser deposition. Transmission electron microscopy (TEM) images revealed that the diameters of the particles two samples were 2.5 and 4 nm. X-ray diffraction was used to determine the purity and lattice constant. Both samples were in the cubic 1-3-m phase. The lattice constants increased with diameter: the 4- and 2.5-nm samples had constants that were 0.42% and 0.55% larger than the lattice constant of the bulk, respectively. Superconductivity behaviors were determined by experiments on magnetic susceptibility. No Meissner effect was observed in the 2.5-nm nanoparticles. The Tc of the 4-nm nanoparticles was about 5.4 K, and accompanied a Hc of about 500 Oe. The critical diameter of vanadium nanoparticles for superconductivity can be estimated using Kubo theory1,2. The calculated critical diameter of the Kubo gap for superconductivity (~ 1.6 meV) is about 3 nm. This fact is believed to be the main explanation of the lack of superconductivity in 2.5-nm nanoparticles.