Dirofilariosis, caused by Dirofilaria immitis and D. repens, is (re-) emerging worldwide. Dogs are the main reservoirs, while human infection has recently become an important focus of interest and attention. In Argentina, canine D. immitis infection has been described in eastern and northern subtropical and temperate humid regions, but never reported in mid-western arid regions so far. In this research note we report for the first time the occurrence of autochthonous human and canine D. immitis infection in the region.