Liposomes have been widely used as drug carriers. Visible liposomes have recently become more attractive as drug carriers in personalized medicine. Gold nanoparticles (Au NPs) have unique size- and shape-dependent properties based on their surface plasmon resonance. They can be visualized by computed tomography (CT) and laser optoacoustic imaging. In addition, their photothermogenic properties are useful for photothermal therapy and photoresponsive drug release from liposomes. Therefore, complexation of liposomes with Au NPs is of considerable interest. There are three types of complex: Liposomes containing Au NPs in the inner phase, liposomes with Au NPs at the lipid membrane, and liposomes modified with Au NPs on the surface. This chapter focuses on the preparation and characterization of the third type of complex that is prepared by direct mixing of a Au NP dispersion with a liposome suspension.