A series of core/shell, iron oxide nanoparticle embedded magnetic mesoporous silica nanoparticle materials with radial (MMSN-r) and hexagonal (MMSN-h) porous structures are synthesized and their capacity to load and release the anticancer drugs, 9-aminoacridine (9AA) and camptothecin (CPT) are investigated. Although effective release of 9AA is observed for nonfunctionalized MMSN, its release from the phenylethyl-functionalized hexagonal MMSN material (Ph-MMSN-h) was hindered. Conversely, the loading and release of CPT is promoted by the presence of the phenylethyl functionality inside the mesopores of MMSN, whereas very low release of CPT was observed from nonfunctionalized MMSN material. Controlled-release properties of the drug-loaded magnetic materials were confirmed by viability studies on Chinese hamster ovarian (CHO) cells, which revealed efficient cytotoxic activity of CPT-loaded Ph-MMSN-h and 9AA-loaded MMSN-h materials. In addition, it was demonstrated that applying an external magnetic field to induce agitation of the drug leaded materials promoted the release of anticancer drugs from the magnetic materials. It is envisioned that the MMSN materials could be effectively applied for externally controlled, selective drug delivery to tumor tissues.