Magnetic resonance imaging (MRI) is one of best imaging technologies to monitor transplanted stem cells, because of its high anatomical resolution and safety. In this study, we aim to synthesize Poly (styrene sulphonate) coated Gd3+ - Poly (lactide co glycolic acid) Perfluorooctyl Bromide nanoparticles (PSS-coated Gd3+@NPs) for stem cell labeling using both 1H and 19F MRI. At a weight ratio 20 of PLGA/ Gd3+, NPs have a spherical shape with the hydrodynamic size at 180 nm with zeta potential at -53 mV. In vitro, we obtain the intended T1 relaxation acceleration of water on 1H MRI. The NPs have low toxicity to the human mesenchymal stem cells (hMSC) up to 1 mg/ml. They could internalize into the stem cells via caveolae-mediated endocytosis efficiently, confirmed by flow cytometry analysis, and gives a good contrast in both channels 1H and 18F MRI scans. In conclusion, our NPs have shown a great potential as a dual-contrast agent in MRI for stem cell monitoring.