Nanomaterials have revolutionized the drug delivery and therapeutic industry due to their unique physical characteristics, which render them extremely manipulative at nano-scale. One such category of nanomaterials is mesoporous silica nanoparticles. Due to their small size and rigid honeycomb-like structure, they are highly conducive for packaging of drugs, dyes, antibodies, etc. In addition, they show excellent biocompatibility. These new generation nanomaterials can be further functionalized by incorporating surface modifications, thus increasing their acceptability as carriers for drugs and molecules. In this chapter, a brief and comprehensive review covering various aspects of the recent advancements in synthesis of mesoporous nanomaterials and post-synthesis strategies for functionalization has been presented. Further, it also sheds light on how efficiently these smart nano-carriers are involved in transport and site-specific delivery of highly toxic drugs, like chemotherapeutic agents for cancer treatment, and their biocompatibility evaluation from a biosafety point of view.