It's perhaps not surprising that the largest city in the Southern Hemisphere has an absolutely enormous and quite fabulous gay pride celebration each year, but the magnitude of the Sao Paulo Gay Pride Parade is still astounding. Brazil is still a predominantly Catholic and in some ways conservative country (although increasingly progressive when it comes to LGBT rights), and the city's Pride parade, known officially in Portuguese as the Parada de Orgulho GLBT de Sao Paulo and produced by the APOGLBT, only began in 1997, when it drew an attendance of a couple of thousand. Fast-forward to 2011, and the parade drew nearly 4.5 million participants and spectators - it's now recognized by the Guinness Book of World Records as the largest Gay Pride celebration in the world. Sao Paulo Gay Pride has shifted its dates a bit, moving to late May and early June - the dates this year are May 30 through June 3, 2013.
The actual Sao Paulo Gay Pride Parade occurs on Sunday, June 2, at noon. It commences outside the Museu de Arte Moderna de Sao Paulo (MASP), at Aveninda Paulista. The city absolutely pulses with parties, not to mention several related events, during the days leading up to Pride and throughout the weekend. Here's a full program of Pride-related events.
Additionally, numerous bars as well as gay-popular restaurants, hotels, and shops have special events and parties throughout Pride Weekend. Check the Sao Paulo Gay Guide at NightTours.com and the Gay Section on Sao Paulo at TimeOut.com for information on the gay scene. The helpful Brazil Gay Pride website of tour operator Bookers International has great information on attending Pride and visiting Sao Paulo, and it also offers package travel deals to both Sao Paolo and Rio de Janeiro during Pride.
For general information on traveling and touring around Sao Paulo, be sure to visit the excellent About.com Brazil travel site. Also take a look at the excellent visitor site produced by the Brazil Ministry of Tourism.