In this study, titanium dioxide (TiO2) was incorporated into solid lipid nanoparticle (SLN) formulations using both classical and novel preparation methods. The SLNs were investigated by evaluating their stabilities and physicochemical characteristics. UV-protection abilities of formulations were investigated using in vitro Transpore™ and Sun To See™ test methods. Results have been discussed by comparing the classical SLN formulation with the novel SLN, hybrid SLN (H-SLN) and the emulsion formulations. The results showed the superiority of the H-SLN formulations compared with the classical SLN; all SLN formulations were better when compared with the emulsion formulations considering the UV protection. Incorporation of TiO2 as a sunscreen agent into SLN formulations gives opportunity to produce stable and safe formulations with reduced amount but high UV-protection ability. © 2006 Society of Cosmetic Scientists and the Société Française de Cosmétologie.