The 68 Ga-labeled iron oxide (Fe 3 O 4 ) nanocomposites ( 68 Ga(NF)HFCNP) have been fabricated for positron emission tomography (PET)/magnetic resonance imaging (MRI) diagnosis and targeted cancer therapy. These radioisotopes labeled nanocomposites with folate conjugation have improved the targeting property toward cancer cells. The chemotherapeutic drug doxorubicin (DOX) was loaded with 68 Ga-labeled Fe 3 O 4 nanoparticles ( 68 Ga(NF)HFCNP) via intermediate DOX-Fe 2+ complex. The average loading efficiency of DOX was 35% for NFHFCNP and 41% for HFCNP, respectively. In drug release profile, the release rate of DOX from the nanocomposite was increased with respect to time. The cell lines, KB and A549 treated with 68 Ga(NF)HFCNP showed high cell viability and excellent cell uptake. Meanwhile, the DOX-loaded nanocomposites exhibit high cytotoxicity toward these cell lines. These properties make 68 Ga(NF)HFCNP nanocomposite as a potential dual theragnostic probe for PET/MRI and targeted chemotherapy for cancer cells.