The anatomical changes in barley (Hordeum vulgare L.) cv. Esmeralda roots caused by C. galinsogae, collected at 10, 20, and 40 days after plant emergence at Singuilucan, Hidalgo are described. It is a recently described pathogen, whose lessions induced on the host plant are unknown. The histological exam showed the 10-day-old juveniles (J2, J3) in the cortical tissue, breaking of neighbouring cells being observed. At 20 d, the juveniles (J3, J4) were found close to the vascular cylinder. Furthermore, the induction of lateral primordia near the nematode was observed. The feeding sites, small and irregular, covered less than 50% of the vascular cylinder and the cortical tissue, with dissolution of internal, and thickening of external cell walls and with disorganization, displacement, and breaking of xylem and phloem. At 40 d, in the cross sections, syncytia were larger, covering 50 to 60% of the vascular cylinder. At cell level, the changes were similar to those observed at 20 d, besides starch being present in abundance. Mature females were observed in the cortex, surrounded by a layer of cork cambium, and the males appeared bent in the same tissue.