Background: Magnetic resonance imaging (MRI) plays an essential role in molecular imaging by delivering the contrast agent into targeted cancer cells. The aim of this study was to evaluate the C595 monoclonal antibody-conjugated superparamagnetic iron oxide nanoparticles (SPIONs-C595) for the detection of breast cancer cell (MCF-7). Methods: The conjugation of monoclonal antibody and nanoparticles was confirmed using X-ray diffraction, transmission electron microscopy, and photon correlation spectroscopy. The selectivity of the nanoprobe for breast cancer cells (MCF-7) was obtained by Prussian blue, atomic emission spectroscopy, and MRI relaxometry. Results: The in vitro MRI showed that T₂ relaxation time will be reduced 76% when using T₂-weighed magnetic resonance images compared to the control group (untreated cells) at the dose of 200 μg Fe/ml, as the optimum dose. In addition, the results showed the high uptake of nanoprobe into MCF-7 cancer cells. Conclusion: The SPIONs-C595 nanoprobe has potential for the detection of specific breast cancer.