Yes, voting is compulsory (required by law) in Brazil. Citizens can also cast a null/blank ballot if they feel that the candidates on the ballot should not be elected. Despite this, only 76% of citizens actually voted in the last presidential election. 69% of the population voted for one of the candidates, only 7% voted null/blank. [1]

1: https://en.wikipedia.org/wiki/Brazilian_general_election,_20...

I live in the US and there's no close (as in commute distance) consulate to where I live. I have the option to justify my absence from voting.

Edit: it's actually pretty neat BTW. My state offers and online system and I can get done with the justification in less than 5 minutes.