Prates is a Portuguese surname with branches in Portugal and Brazil. According with books from The Tombo's Tower Library (Portugal) is 'a Family of very noble and old origin and descend from 'van Praet'. Some members of the Netherlands (presumably cadet branch) moved first to Antwerp (Belgium) and was subsequently settled in Portugal, in the person of Jácome van Praet. Turning generations the surname 'van Praet' took the Portuguese form of 'Prates'.
António Prates came to be General Secretary of the Board of Three States, Judge of the Court of the Holy Office, Knight of the Order of Christ and Lord of Póvoa de Santa Adrião. Received its own Coat of Arms (Prates) and he was relegating the old Coat of Arms of Praet ('van Praet').
Again, turning more generations three brothers Prates immigrated to Brazil: Hermenegildo Rodrigues Prates went to Minas Gerais State; João Rodrigues Prates went to Rio Grande do Sul State and the third one went to São Paulo State.
And may refer to:

• Júlio Prates de Castilhos (born 1860 - died 1903): Brazilian lawyer, politician and journalist. Governor of The State of Rio Grande do Sul.

See: http://pt.wikipedia.org/wiki/J%C3%BAlio_de_Castilhos
pt.wikipedia.org/wiki/Júlio_de_Castilhos

• Count of Prates (Conde de Prates) - Eduardo Prates (born 1860 - died 1928): Brazilian businessman and farmer
• Raquel Prates (born 1976): Portuguese TV presenter
• César Prates (born 1975), Brazilian football defender
• Jair Gonçalves Prates
  Jair Gonçalves Prates
  Jair Gonçalves Prates, was a Brazilian football player who played as an attacking midfielder.Jair made 137 Campeonato Brasileiro appearances for Internacional.- Biography :...
  
  (born 1953), Brazilian football striker

To check about 'van Praet' see: http://en.wikipedia.org/wiki/Louis_of_Praet