Magnetic resonance imaging (MRI) is one of the best imaging modalities for noninvasive cancer detection but MRI does not have enough sensitivity to delineate tumor margins during surgery. Moreover, since most surgical tools contain metal substances, image-guided surgery is hard to perform with a MR machine using magnets. Also, MR imaging is too slow for real-time guided-surgery. On the other hand, near infrared fluorescence (NIRF) imaging has recently received great interest for in vivo imaging due to its high signal-to-noise ratios and short image-acquisition times. NIRF imaging can be used to delineate tumor margins during surgery, but current NIRF imaging cannot provide the penetration depth to detect early-stage cancer inside body. Thus, we have developed dual-modality in vivo imaging for MRI detection of tumors and NIRF-guided surgery using multi-component nanoparticles. NIRF dye (cyanine 5.5, Cy5.5), conjugated glycol chitosan nanoparticles (HGC) exhibited excellent tumor targeting ability with NIRF imaging. Superparamagnetic iron oxide (SPIO) nanoparticles as a MR contrast agent were loaded into the nanoparticles, resulting in SPIO-HGC-Cy5.5 nanoparticles. SPIO-HGC-Cy5.5 nanoparticles were characterized and evaluated in mice by both NIRF and MR imaging. Our results indicate SPIO-HGC-Cy5.5 nanoparticles have the potential for dual-modality in vivo imaging with MRI detection of tumors and NIRF-guided surgery.