Pentraxin 3 (PTX3) is an acute phase protein which regulates peripheral inflammationand it has been suggested to have neuroprotective properties. Inflammation iscommonly associated with poor outcome during diverse central nervous system (CNS)disorders, but the role of PTX3 in brain inflammation is completely unknown. Westudied the role of PTX3 in brain inflammation and repair after stroke, a CNS disorderwhich is the third cause of death worldwide. To induce ischaemic stroke, we used themiddle cerebral artery occlusion (MCAo) model and found that the pro-inflammatorycytokine interleukin (IL)-1 was the inducer of PTX3 expression in the brain. Theanalysis of markers of inflammation and repair up to 14 days after MCAo in wild typeand PTX3 knockout (KO) mice revealed that, in general, lack of PTX3 has a negativeeffect on recovery after MCAo. PTX3 KO mice had delayed oedema resolution,defective glial scar, impaired microglial proliferation and reduced angiogenesis andneurogenesis. Therefore, PTX3 emerges as a target for stroke recovery and possiblyother CNS inflammatory diseases. PTX3 was, however, not involved in remoteneurodegeneration in the substantia nigra (SN) (an area of the brain remote butconnected with the area affected by the stroke), but we observed that remoteinflammation preceded remote neuronal death in the SN. Therefore, prevention ofremote inflammation may help prevent remote neurodegeneration in the SN afterstroke. This could have long term implications in SN neurodegeneration, which is akey pathological feature of Parkinson´s disease.