In current cancer therapy, the combined targeted delivery of treatments is an important method to enhance the therapeutic efficiency and reduce adverse side effects. Dendrimer-based nanoparticles have received considerable attention for multifunctional therapeutic delivery. In this chapter, we describe the methods for encapsulating the chemotherapeutic drug, cisplatin (CDDP), and human antigen R (HuR)-targeted siRNA into dendrimer nanoparticles for folate receptor-targeted delivery. We discuss the methodologies for physical and biological characterization of synthesized multifunctional (Den-PEI-CDDP-HuR-FA) nanoparticles in detail. Physical characterization includes size and charge determination, drug encapsulation and release kinetics, ligand conjugation, etc., and functional characterization involves testing of the nanoparticles for receptor-specific uptake and cytotoxicity on human lung cancer and normal cells. The protocol provided is geared to provide the readers an overview of developing multifunctional dendrimer-based nanoparticles. However, based on the individual's objective and the type of combinatorial drugs to deliver, the protocol may need modifications in achieving maximal efficacy.