Osasco is a municipality and city in São Paulo State, Brazil, is located in the Greater São Paulo and ranking 5th in population among São Paulo municipalities. The current mayor is Emidio Pereira de Souza (PT). It is among the World more dense cities, similar in density to Tokyo and New York City. It's considered the major urban centre of the Western portion of the Greater São Paulo. It used to be a district of São Paulo City until February 19, 1962, when Osasco became a municipality of its own. In 1989 the city became the seat of the Roman Catholic Diocese of Osasco.