The clustering properties of sub-critical 3D Lennard-Jones particles have been determined by Monte Carlo computer simulation. The goal was to study liquid formation, which results in the definition of a cluster that is based on the radial distribution function of the LJ liquid. The cluster distribution was compared with that predicted by classical nucleation theory and analyzed with the cluster distribution scaling law. It was found that the surface tension must vary with cluster size in order for classical theory to fit the simulation data. Also, the scaling law was determined to have limited usefulness over the range of system densities and was most applicable to lower densities and higher temperatures. The density profile revealed that the clusters did not have well defined surfaces and were liquid-like in the interior. The fractal dimension was calculated from the radius of gyration and found to agree with the accepted value. The presence of a phase transition was determined from the cluster energy plots.