A couple of folks have mentioned that the Brazil visa is valid for 90 days or five years. This, I think, is not quite correct. While the Consulate can determine the length of validity and number of entries on any particular type of visa, the most common visa issued is for Tourist purposes and is a 5 year multiple entry visa that MUST be used at least once within a 90 day period. If the bearer of such a visa fails to enter Brazil within the ninety days, the visa is no longer valid.

I have read about one person's experience on FT, or maybe another forum, where they obtained a visa for Brazil and entered at Iguacu Falls, where passports are often not stamped. Theirs wasn't. When they subsequently tried to return to Brazil again, it wasn't possible with that visa.

Another personal experience was at the DC Consulate where an elderly lady, a US citizen, started taking to me as we waited. She had been denied boarding at IAD because the airline agent stated that her 5 year visa had not been used within the 90 day period. They instructed her to go to the Consulate. Unfortunately for her, her passport had been stamped, but it was very faint and difficult to see. Perhaps the agent was too busy to look closer, who knows, and I don't know what happened to her at the Consulate, but the point is, when you enter Brazil with this type of visa, make sure it is stamped and make sure the stamp is easily visible.