Shuttle-like crystalline TiO2 nanoparticles were synthesized by hydrolysis of titanium tetrabutoxide in the presence of acids in NP-5 (Igepal CO-520)–cyclohexane reverse micelle at room temperature. Pure rutile nanoparticles were obtained at appropriate acid concentrations. The influences of various reaction conditions, such as concentration and type of acid, water content, H2O/Ti molar ratio, and reaction time, on the formation, crystal phase, morphology, and size of the TiO2 particles were investigated.