The two men, aged 78 and 51, were said to be in a "serious condition" in hospital after the injuries sustained while watching the "encierro a caballo" - when the bulls run through the streets to the bullring guided by men on horseback - on Sunday morning.
Two bulls broke away from the pack of six and broke through a metal barrier sparking panic among the crowds.
But the two men felt the full force of the half-tonne beasts as they perched atop the fencing to watch the bull run.
In the video below a spectator captured the moment one man was gored as he sat astride the fence while another was knocked to the ground.
The bull's horn pierced the right thigh of the older man delivering two wounds of 20cm in length and one of 15cm and another in his left leg of 20cm. His son was also gored in the right thigh.
The annual Carnaval del Toro takes place in Ciudad Rodrigo, a city between Salamanca and Spain's border with Portugal where a makeshift bullring is set up in the historic Plaza Mayor.
During the same festival last year, a Scottish grandfather told The Local how his head was "split open" by a bull's horns.
Last summer was particularly bloody in terms of bull running incidents with 13 people killed during bull runs across Spain.