The built up regions of São José dos Campos and the neighboring city of Jacareí have merged in the last two decades. The estimated population of both cities is 841,000 inhabitants.
The large population growth that occurred in the city was a result of continuous migration from other regions of the country. As a consequence, in 1991, people that were born in São José dos Campos represented only 47% of population (according to IBGE). According to a new research from Univap, this number increased to 49.83% in 2004.
In the city, the population (according to census 2000) was spread out with:24.2% under the age of 14 20.1% from 15 to 24 47.4% from 25 to 59 8.2% who were 60 years of age or older.
The city's ethnic composition (according to census 2010) is 72.61% whites; 21.4% brown; 4.48% blacks; 1.44% Asian; 0.08% amerindian.