The attack occurred near Kfar Qara, south of Haifa, Ynetnews.com reported. The hiker, a 56-year-old man, was conscious and was able to call for help on his cellphone.
Paramedics treated the hiker at the scene and he was then transported to the Hillel Yaffa Hospital in Hadeera. He had broken bones in his lower body, doctors said.
The hiker told the sheep slammed into his lower body.
Sheep attacks are relatively rare. The last one reported in Israel occurred in 2009 when a boy was bitten by a rabid sheep.
The Israel National Trail extends about 600 miles from Dan near the border with Lebanon to Eilat on the Red Sea.