Sand screen selection relies on accurate particle size information for the sands that need to be controlled. Within the oil industry there is awareness of the differences between dry sieve analysis and laser particle size analysis (LPSA), but there can also be wide variations between LPSA performed in different laboratories even when such variables as sample preparation are taken into consideration. Recent work by the authors has shown that such variables as sonication time and amplitude can have a significant effect on certain sands, and there is evidence to indicate that the sensitivity to sonication is dependent on the mineralogy of the sand. Other factors have also been examined to address the widespread view within the oil industry that LPSA exaggerates the fines content, whereas the opposite view is held in sedimentology and soil science in that the coarse fraction is believed to dominate. Work has been performed to examine which view might be most relevant for reservoir sands, and guidelines for performing LPSA are proposed.