The deep biomedical knowledge reached in the past decades in many fields of medicine and biology has been accompanied by continuous technological progress in measurement instrumentation and analysis techniques. This development is important also to improve the characterization and the understanding of the interactions between nanoparticles and biological liquids, due to emerging applications such as drug delivery, bioimaging, biosensing, diagnostics and photothermal therapy. In this study, we characterize the interaction between mouse serum and gold nanoparticles (NPs) and nanorods (NRs) by Modulated 3D Cross-correlation Dynamic Light Scattering (DLS), in order to demonstrate that this technique can be applied to the investigation of complex biological liquids. The analysis of the size distribution of the hydrodynamic radius reveals three different contributions from particles motion, associated to rotation, translation and agglomerates. Moreover, we show that the interaction between Au NPs or NRs and mouse serum depends on the aspect ratio of the Au particles. These results are promising for deepening the knowledge on proteins-nanoparticles interaction, for laboratory-based experiments as well as for sensing and diagnostic applications and nanoparticles based medical therapy.