While studies on the wage effects of immigration focus on native workers, there is significantly less information on the wage effects of immigration on domestic foreign-born workers. In addition to analysing the impact of immigration on wages of native workers, in this article, we estimate the internal competition among foreign-born workers in the United States. Firstly, using data from the Current Population Survey, we find no empirical evidence supporting the substitutability of native workers for immigrants. Secondly, there is no statistical difference between skilled and unskilled immigrants on the influence of the domestic labour market outcomes. Finally, there is no internal competition among immigrants. The income of non-citizen workers mainly depends on state and national levels of economic situations, not the number of non-citizen workers available in the labour market.