Paramedics said the man was working on his tractor at his farm on William Mooney Road near Carp in the west end of Ottawa when the axle caught a piece of his clothing and then his arms.
The accident severed both of his arms — one at the shoulder and one at the elbow, according to paramedics.
Emergency crews were called at about 8 a.m. and rushed him to hospital. He was in critical condition at the time of his arrival at the hospital.
The Ontario Ministry of Labour is also at the scene.