Officials said the victims, aged 46 and 27, were taking part in festivities late Friday in Moita, a small town about 30 kilometres south of the capital, Lisbon.
At the annual town festival, bulls are set loose in the downtown streets, which are fenced off, and people can run into the street to taunt the animals. Thousands of people attend the festival.
Officials said today that spectators are warned of the dangers of entering the barricaded streets where the bulls run free.