Migration is unarguably the most influential process that has determined what the Kerala state now. That much impact the process has as far as all the fields of life in the state is concerned. This process of emigration facilitated the replacement migration of the labourers from other state of Kerala. Replacement migration is mainly due to the large scale migration of young working population along with the unwillingness of the people of Kerala to do manual works. A large number of migrant labourers got attracted to the state due to high wage rate, and better working and living conditions, which helped to reduce this imbalance between demand for and supply of labour. This labour in-migration obviously affected the economy and society to a great extent not only in positive but in negative terms also. One of the major adverse effects of in-migration is supposed to be in the labour market of the native workers. This paper examines whether the labour migration to Kerala is competitive or complementary to the native workers. This is examined in the framework of the competitive and complementary effect aspect of Borjas’ theory of Immigration and supported by the evidences from the primary survey. The study finds that in-migration in the present context is not a threat to the native workers as majority of the in-migrants is unskilled or semi-skilled who are not competitive to the skilled native workers of Kerala.