Efficient and safe drug delivery has always been a challenge in medicine. The use of nanotechnology, such as the development of nano drug delivery systems (DDS), has received great attention with high enthusiasm owing to the potential that nanocarriers can theoretically act as "magic bullets" and selectively target affected organs and cells while sparing normal tissues. The family of nano DDS includes conventional nano drug delivery materials such as lipids and polymers that have been scaled to the nanometer size range. With the rapid development of synthesis and characterization techniques for engineered nanomaterials, new DDS platforms have emerged, including inorganic based nanocarriers, such as mesoporous silica nanoparticles (MSNP). MSNP are able to act as a multifunctional delivery platform that is capable of delivering therapeutic elements to a variety of disease models (especially cancer) at cellular and in vivo levels. Furthermore, MSNP have shown to be exceptional delivery platforms capable of protectively packaging hydrophobic and hydrophilic drug molecules as well as other therapeutic elements for controlled on-demand delivery. In addition, MSNP have demonstrated the capability to image the delivery site for theranostic purposes. These functionalities have led to the development of MSNP as novel multifunctional nanocarriers, and therefore provide them with unique advantages compared to other nanocarriers.