Solid lipid nanoparticles (SLN) have gained increasing attention as a colloidal drug carrier system, particularly for lipophilic drugs, because SLN combine the advantages of polymeric nanoparticles, fat emulsions, and liposomes but avoiding their disadvantages. Solid lipid nanoparticles are composed of high melting point lipid as a solid core coated by surfactants. The solid core allows the prolonged and controlled release of drugs and may protect incorporated drugs against chemical degradation. Lipid and surfactant nature are important in drug loading capacity, also affect size distribution and physical stability. In this study SLN were prepared by using different ratios of lipid/surfactant. The lipid nanopellets were produced by using the high speed homogenizer and by high pressure homogenizer. The particle size measurements were carried out using the photoncorrelation spectroscopy and laser diffraction. The results showed that the diameter of SLN were influenced by lipid matrix and surfactant nature as well as their concentrations. Particle size diameter was decreased as a function of surfactant concentration till it reach a certain limit after which it has no effect. Methods of preparation showed a potential effect on the presence of large particles and on the polydispersity index. In conclusion, physical characteristics of SLN are not only influenced by variation in process parameters but also by chemical nature of the used surfactant and lipid matrix that have a potential influence on the particle size distribution of SLN.