Objectives Rheumatoid Arthritis (RA) is one of the most frequent inflammatory diseases, causing pain and disability in the affected joints. Early diagnosis is essential for the efficiency of symptomatic treatment, and relies on careful clinical, serologic and imaging examinations, such as Magnetic Resonance Imaging (MRI), which is both expensive and time consuming. In an effort to provide the biomedical community with a more accessible way to assess arthritis advancement, we investigated the use of multispectral optoacoustic tomography (MSOT) in a murine model to visualize the extent of the inflammation in vivo through a L- and P-selectin targeting contrast agent. Methods Collagen induced arthritis mice were used as a rheumatoid arthritis model of the limb. MSOT was performed using a L- and P-selectin targeting contrast agent (dPGS-NIR provided by Mivenion, Germany) to increase contrast of the arthritic joint, and signal intensity ratios between healthy and arthritic legs were calculated. Contrast enhanced MR imaging as well as clinical observation, lymphocyte/granulocyte ratio and histology served as references. Results MSOT using an inflammation targeting contrast agent allowed for accurate diagnosis of inflammation in the mouse joints and for significant differentiation of inflamed to healthy joints (P = 0.023). The arthritis findings on the MSOT images were confirmed by clinical observation, blood analysis, contrast enhanced MRI and ex vivo histological examinations. Conclusion This study demonstrates that the combination of inflammation targeting contrast agent and optoacoustic tomographic imaging present a promising mean for diagnosis and staging of arthritic inflammation.