We propose and demonstrate a new method for fabricating periodic arrays of metal nanodots over a large area. In this method, metal nanogratings were first patterned on a substrate by nanoimprint lithography and lift-off, and were then melted using a single excimer laser pulse. We found that the laser melting broke the metal nanogratings into periodic nanodots. Furthermore, we demonstrated the control of the nanodot array pitch using a substrate surface topology, and the fabrication of two-dimensional periodic metal nanodot arrays of 70 nm diameter and 200 nm period. The fragmentation of lines into dots was attributed to the Rayleigh instability in a liquid cylinder.