Serum NGF concentration was increased in lame horses with radiographic evidence of osteoarthritis (P < .0001; median, 238 pg/mL; interquartile range [IQR], 63‐945 pg/mL) and in lame horses without radiographic evidence of osteoarthritis in the painful joint (P < .05; median, 31 pg/mL; IQR, 31‐95 pg/mL) compared with sound horses (median, 31 pg/mL; IQR, 31‐46 pg/mL). Here, NGF is linked to osteoarthritis.