The last ten years mesoporous silica nanoparticles(MSNs) have been extensive investigated as a drug delivery system. It is well know that MSNs possess excellent properties such high specific area, high pore volume, tunable pore structures and physicochemical stability. In the beginning MSNs were used for controlled delivery of various hydrophilic or hydrophobic active agents. Later advances in the MSNs surface properties such as surface functionalization and PEGylation rendered them as a promising drug delivery vehicle for cancer treatment.