[Objective] We have developed a less invasive transient middle cerebral artery occlusion (MCAO) model on primates, common marmosets, without invasive procedure including craniotomy. Behavioral assessments (motor paresis, sensory disturbance and visual field defect) , MRI and positron emission tomography (PET) were performed with time postoperatively. And then, we checked whether our model would be useful for cell therapy. [Method] Female laboratory-bred common marmosets were used. Under anesthesia, wire thread was inserted into right MCA via carotid artery. We used 3 hours occlusion. Behavioral assessments, MRI and PET were performed postoperatively. In PET study, we used BCPP-EF, which is ligand to the complex1 of mitochondria. Transplanted cells were neural stem cells or precursor cells of a marmoset embryo brain. [Result] At postoperative day 7, MRI T2 weighted image showed brain infarction on right hemisphere including basal ganglia as high intensity lesion. However, after 28 days, the high intensity area was reduced dramatically. In PET, BCPP-EF showed the comparable result. Behavioral tests exhibited neurological deficits with left hemiparesis deteriorating for 4 days after surgery. After that, neurological function improved gradually. Six weeks after surgery, the behavior did not recover completely. Remained motor paresis such as ham hand could be observed by food retrieval test. The immunohistochemical study also showed defect of neural cells on the lesion. There were no complications by transplant. Transplanted cells could be checked by PET. [Conclusion] We have developed less invasive marmoset MCAO model. MRI, PET and behavioral tests showed reasonable brain infarction as well as human. The model is considered to be useful to evaluate the effect of the cell therapy of the cerebral infarction of the primates.